The Army helicopter banked low over the broad deltaic plain where the mighty Ganges River flows to the Bay of Bengal, swept over flooded rice paddies where peasants stooping over their meager harvests gave only desultory notice, and settled onto a soccer field in this seaside resort town for the day's fourth and last barnstorming stop.

Looking more like an eager political candidate on the hustings than a firmly entrenched military strongman--despite his neatly pressed jungle fatigues and combat boots--Lt. Gen. Hussein Mohammed Ershad bounded from the aircraft and waded into a crowd of well-wishers waiting to dedicate a new government-owned guest house.

The speeches that followed were not unlike those of nearly a dozen other visits in a recent week to sugar mills in northern Bangladesh, government offices in Dhaka, a meeting of Islamic scholars, Army bases and remote villages: The martial law administration, which seized power in a bloodless coup March 24, is striving for economic emancipation for the masses of poor people; a holy war is being waged on corruption and inefficiency; the social and political order of Bangladesh should "breathe" Islamic principles, and moral deterioration must be reversed.

Ershad, a soft-spoken, almost shyly polite officer whose youthful looks belie his 52 years, is clearly a man on the go, but nobody is quite certain where he is going.

He has been tirelessly dashing about Bangladesh for months, taking his promise of political and economic stability to the people of a desperately poor country that understands the finite nature of resources, and that historically has been on the knife's edge of disaster, both natural and political.

His critics say that Ershad is trying to legitimize a military dictatorship with worn-out palliatives, offering rhetoric as a substitute for democracy, and that he has no intention of holding elections.

His supporters say that he is simply trying to bring order and discipline to a country that persistently courted anarchy as it underwent a seemingly endless series of bloody coups and attempted coups, and which in its last chaotic national election had 75 candidates running for the office of president.Ershad says he is seeking to lay the foundation for a return to civilian democracy, and that skeptics who find his rhetoric similar to the five years of pledges of restoration of democracy by Pakistani martial law administrator Mohammed Zia ul-Haq will have to trust him.

In an interview in his helicopter as he toured the country last month, Ershad would not commit himself to a specific date for national elections to reconstitute the disbanded parliament, but he hinted broadly that it could be as soon as the end of 1984, or shortly after.

"As a nation, we Bangladeshis love politics. Politics must come back, we know that. But politics doesn't always mean progress. We have to first instill discipline and self-control in the country, and that doesn't mean having 75 candidates running for president," Ershad said.

But whenever democracy is restored, Ershad said, the military must still have a role to play in government.

"We can recall our contribution to the development of the country," said Ershad, who imposed Bangladesh's second martial rule after ousting Abdus Sattar, an aging former Supreme Court justice, from the presidency.

"The Bangladesh Army is a political entity because we fought for the national cause," Ershad said, referring to the 1971 civil war after which Bangladesh was created out of East Pakistan. "The military must have a role to play," he said.

Asked whether he would take off his uniform and run for president, Ershad smiled and replied, "I haven't decided yet. We'll see."

Opposition leaders say that whether Ershad runs for president--and most of them expect him to--the elections will inevitably bear the strong imprint of the martial-law government.

Already, opposition activists maintain, candidates handpicked by the military government--many of them government officials--dominate the local-level nominations.

Opposition parties are not banned in Bangladesh, but political activity is. As a result the opposition is disorganized, fragmented and without funds. Moreover, while there is no formal press censorship, reporters who dare write critically of the military government are summoned to the austere, barracks-like martial law administration secretariat for questioning and a harsh reprimand.

"It doesn't take long to get the picture," one senior reporter for a major daily newspaper said.

The state-run television and the front pages of most newspapers are dominated by flattering stories of Ershad's speeches and helicopter tours, more often than not written by the general's personal press secretary and distributed by the state-owned news agency.

The Bangladesh Nationalist Party of former president Gen. Ziaur Rahman dominates the opposition, but its activities are largely restricted to salon politics and some university campus activity. The severely compromised and fractious Awami League, which from 1972 to 1975 ran the country's economy into the ground and plundered government funds with corruption, is no longer a political force of note.

Also, a number of formerly prominent politicians have been swept up by Ershad's much-heralded anticorruption drive.

Opposition activists maintain that many of those arrested had been involved in an effort to revive the Bangladesh Nationalist Party.

But some political observers here note that Ershad's proclaimed jihad, or holy war, against corruption has not lived up to his harsh rhetoric, and that sentences, when imposed, have so far been relatively mild.

Apart from a 1 a.m.-4 a.m. curfew, there is little visible evidence that a martial-law government is in power, and many Bangladeshis admit that the military takeover has hardly restricted their lives. In the fading elegance of the Dhaka Club, an old British retreat where businessmen, politicians, lawyers and journalists debate, criticism of the Ershad government flows as freely as the drinks in spite of penalties on the books for speaking against the government.

Army colonels and majors, some of them uniformed and some retired, have moved into many government offices, causing anxiety among civil servants. In October, a civil service commission put 555 public employes on notice that they are under investigation for corruption or inefficiency, causing more insecurity in the ranks of public employes.

Ershad, who is said to be almost obsessive about neatness, recently made a surprise, white glove-type inspection of one government building, rebuking bureaucrats for haphazard stacking of obsolete documents in untidy offices and criticizing furniture arrangement.

"The chief won't tolerate messiness in the government any more than he would in the Army," said one martial law official of Ershad, who is also chief of staff of the Army and officially is called the chief martial law administrator.

Ershad also has vowed to transform Bangladesh into an Islamic state, but he has begun cautiously and with the appearance of possibly being motivated as much by Saudi Arabia's considerable financial assistance to Bangladesh as by any personal Islamic fervor.

In a speech last month to Islamic scholars, Ershad promised that Islam would have a "pivotal position" in any future constitution, and that "all future plans of the state will then be implemented on the basis of the principles of Islam."

But in an interview, the military ruler appeared to adopt a more flexible stance, saying that the "spirit" of Islam would be incorporated in Bangladesh, but that he did not intend to follow the example of Pakistan, which has established Islamic law courts.

The most pressing challenge, Ershad said, is to stabilize the economy of Bangladesh, where the average per capita income is $100, where the literacy rate is only 20 percent and where 80 to 90 percent of the 90 million people live in poverty.

Bangladesh, whose human and economic infrastructure has repeatedly been ravaged by floods, droughts, wars and other natural and man-made calamities literally survives on foreign aid.

Total foreign aid currently is $1.3 billion, or slightly more than Bangladesh's total development budget. This year, total U.S. aid since the country won independence in 1971 will pass the $2 billion mark.

The United States now gives Bangladesh about $80 million a year in development aid and another $80 million in agriculture commodity aid. The U.S. development grants are second highest--behind the $85 million India gets--to any country except those considered strategically critical, such as Egypt, Israel and Pakistan.

Ershad appears sensitive to the need to accelerate efforts begun by former president Zia to get Bangladesh out of the welfare dependency cycle and into real economic development, and has stepped up Zia's program of denationalizing industries that had stagnated in inefficiency and corruption under state ownership.

In a surprise move, Ershad also ordered the sale to private interests of four government-owned daily newspapers, including the English-language Bangladesh Times and The Observer, and three weeklies. Government ownership of newspapers dates back to independence, and in 1975, the government of Mujibur Rahman, after introducing one-party rule, closed down all of the remaining privately owned newspapers.

With gentle but persistent prodding by donor nations, Ershad's government is gradually turning back to the private sector a third of the 70 percent of total industrial assets that had been owned by the state.

With a population growth rate of 2.8 percent, and projections of a doubled population by the middle of the next century, Bangladesh still faces formidable hurdles on the road to economic recovery.

And even when it does achieve self-sufficiency in food--as it nearly did two years ago in an unusually good crop year--the kind of natural disaster to which Bangladesh seems prone, or even a political upheaval and a combination of the kind of untimely economic decisions that have characterized the past, could put the country back into the "basket-case" category once cited by Henry Kissinger.