A new surge of Vietnamese "boat people," nearly doubling the rate early this year, has begun to flood Southeast Asia, raising concerns that many of the problems that dogged the last great refugee wave in 1979 may reoccur.

Attempts to resettle at least some of the refugees in the United States have been delayed by a bureaucratic dispute between the U.S. State Department and the Immigration and Naturalization Service over the definition of a refugee, and the reasons -- economic or political -- for which he leaves his homeland.

This crowded British colony reports twice as many arrivals of Vietnamese refugees this year as during the same period last year. Other Southeast Asian countries also are taking in greater numbers of boat people, although the exodus so far this year does not approach the massive scale of 1979. According to the U.N. High Commissioner for Refugees, more than 10,000 Vietnamese boat people arrived in various Asian countries in April, double the rate of arrivals during the first three months of the year.

Officials here and elsewhere in the region say it is too early to tell whether the increase in boat people signals a major new trend, but they clearly are uneasy about that prospect. "It has always been the case that the tap could be turned on again," said one Hong Kong government official.

Compounding their anxieties is concern that the current dispute between the State Department and the Immigration Service could leave Hong Kong and Southeast Asian countries stuck with resettling the refugees elsewhere. In 1979, some nations in the region dealt with the refugee influx by turning boat people away from their shores.

The current problem stems from legislation passed by Congress last November to amend the U.S. Immigration and Nationality Act. Until then, refugees from Indochina were admitted to the United States under the attorney general's authority on grounds that it was in the national interest.

In an attempt to regularize this procedure, Congress gave the president blanket authority to admit 50,000 refugees a year, with a requirement that congressional approval be sought if the administration wanted to admit more.

The amendment basically defined a refugee as a person who fled his country bercause of persecution or the threat of persecution and who could not return home. The law required Immigration Service district directors to determine who fit the definition before asylum could be granted. Generally, the result has been a tendency to disqualify for resettlement those who cite economic reasons for their departure. Prior to the current surge in Vietnamese boat people, the chief casualties of the new policy have been refugees fleeing Haiti who the Immigration Service contended were merely trying to better themselves economically rather than fleeing persecution.

The State Department, on the other hand, argues that the Immigration Service's concern about circumventing the immigration law is outweighed by foreign policy and humanitarian considerations. At stake, officials say, are U.S. commitments to Southeast Asian governments to relieve some of the burden posed by hundreds of thousands of Indochinese refugees in the last two years. Moreover, there is the fear that if U.S. resettlement drops off sharply, Southeast Asian states would resume the policy of turning away boat people.

The State Department also contends that in some cases the "economic" motivations cited by refugees who say they cannot make a living in Vietnam may derive from political factors. In any case, the department says, once they leave they cannot go back no matter what their reasons.

Because of the State Department's objections, the Immigration Service has agreed not to reject Indochinese refugees under the new law but to defer decisions on their cases until the disagreement is resolved.

Hong Kong government officials and Western diplomats blame growing food shortages and rising inflation in Vietnam for some of the most recent departures. Other refugees lately have been fleeing the draft and the prospect of military service in neighboring Cambodia, where 200,000 Vietnamese troops are battling communist Khmer Rouge guerrillas.

In addition, Vietnamese of Chinese extraction -- who accounted for most of the refugees during the exodus of 1979 -- continue to leave the country, charging discrimination against them by the Hanoi government. Other refugees are South Vietnamese who profess opposition to communism.

While the reasons for leaving Vietnam are more varied than ever, a major contributing factor now appears to be the country's worsening economy.

"In the beginning the great majority came from Central and South Vietnam," a Hong Kong official said. "Now we're getting more from North Vietnam. We're even getting the North Vietnamese farmer." He said this shift began in August and September of last year and that the proportion of south and central Vietnamese among the refugees arriving here currently is about 80 percent.

As a result of the Immigration Service's deferral, about 1,000 people are awaiting a decision from the United States in Hong Kong alone, a senior Western diplomat said. The problem is especially acute for the British colony, which already has the highest population density in the world and where more than 18,000 Vietnamese refugees still await resettlement.

"It's a problem urgently in need of resolution," the diplomat said. "It could have substantial consequences."

A Hong Kong government official expressed a similar concern. "The prospect of the resettlement program being delayed certainly is a problem because the U.S. program is far and away the largest," he said. "Anything that is an obstacle to resettlement has repercussions internationally."

He added, "The longer refugees stay in Hong Kong, the harder it is for them to leave."

Neither official wished to be identified.

Elsewhere, the resettlement snag is just beginning to come to the attention of Southeast Asian governments, diplomats say. As in Hong Kong, they say, the deferrals are a potentially serious problem.