To the Reagan administration, Leon Febres Cordero is a model Latin American leader. But to many here at home, the Ecuadoran president has an image as a hard-knuckled politician out to crush his critics.

A quick-smiling, energetic man with a bushy mustache, Febres Cordero has deftly cultivated warm relations with the United States, pursuing conservative economic policies that have won favor with U.S. banks and a tough line on Nicaragua that has pleased Washington. But he has fought bitterly in Ecuador with opposition politicians and independent editors, who accuse the president of disregarding democratic norms.

In recent days, Febres Cordero also has faced opposition in some quarters of the military. On Friday, Lt. Gen. Frank Vargas Pazos, the armed forces chief of staff and commander of the Air Force, called for the ouster of the defense minister and the head of the Army and then rejected his dismissal by the president for insubordination.

Febres Cordero has set up temporary presidential offices in his hometown of Guayaquil to monitor the crisis, while the rebel general remains at a Pacific Coast Air Force base, Reuter reported. Febres Cordero has put the military on alert and sent troops to ring the base where Vargas Pazos is entrenched.

Critics cite several actions by Febres Cordero as cause for alarm:

*He stationed tanks around the Supreme Court building to prevent 18 new magistrates named by the congress from taking their seats because he objected to the choices. A new group of justices, more to the president's liking, has been selected since.

*He banned publication in the Official Register of congressional acts he opposed. Without publication in the register, the legislation was blocked from taking effect.

*Under his presidency, opposition party members say that they have been fired from public service jobs and subjected to tax audits. News organizations critical of Febres Cordero, including Quito's second-largest daily, Hoy, have found their advertising revenues cut. Journalists sympathetic to the opposition have reported receiving physical threats.

In an interview, Febres Cordero said his sometimes forceful tactics have been necessary to assert presidential authority over a congress that, initially, was controlled by a leftist opposition and resented his election. Several deputies have shifted allegiances, and the president now enjoys a majority in congress.

The president described himself as a "passionate" politician and stressed his respect for the constitution. He said Ecuador has a very free press. "Listen to them," he said. "They call me a son of a bitch."

He packs a Colt .45 pistol for personal safety.

The Inter-American Press Association has criticized Febres Cordero for "demonstrations of intolerance" toward the press and for "using especially radio and television in a form that does not conform with the objectivity that should characterize government communication."

Ecuador, a relatively tranquil nation the size of Colorado, had attracted little such concern since the military ceded power in 1979 to a democratically elected president, Christian Democrat Jaime Roldos. His death in a 1981 plane crash shocked the nation. But vice president Osvaldo Hurtado took over and, faced with the decline of the oil exports that had buoyed the economy in recent years, pushed through austerity measures that left Ecuador in a better situation than most of its debt-stricken neighbors.

When Febres Cordero was elected president in 1984, it marked the triumph of the industrial port of Guayaquil over Quito. The business-oriented port long has resented controls imposed from the capital.

Febres Cordero, a hard-charging businessman, seems to personify the dynamic spirit of the industrial port versus the cooler temper of Quito, high in the mountains. There were warnings that his domineering personality and conservative economic program would cause political polarization. Opposition members and some independent analysts say that is what has happened.

"We live in a democracy more apparent than real, and the government pursues a path of concentration of power," said Rodrigo Borja, the social democratic party leader and native of Quito who lost to Febres Cordero in the presidential race.

"I don't remember a time when a government has been so abusive, so arbitrary as this one," said ex-president Hurtado. "The United States has ignored the antidemocratic facts here. Ecuador has been Uganda-ized. This is not a model; this is an aberration."

One fear is that Febres Cordero's aggressive style and conservative policies will encourage the growth of left-wing terrorism. A guerrilla group, Alfaro Vive, surfaced in 1983. Named after a crusading general, Eloy Alfaro, who led Ecuador at the turn of the century, it asserted responsibility for the theft from a Guayaquil museum of Alfaro's sword.

Believed to have ties with Colombia's M19 guerrillas, the Ecuadoran extremists have been accused of kidnaping, robbing banks and taking over radio stations to broadcast attacks on the government.

What makes the U.S.-educated Febres Cordero most appealing to the Reagan administration has been an economic program that favors free enterprise and foreign investment. The policy is unusual on a continent where the government's role in the economy has grown dramatically over the years.

In the 19 months since Febres Cordero took office, he has reduced governmental subsidies and price controls, promoted private enterprise, eased import restrictions and improved the climate for foreign investment in Ecuador, particularly in petroleum and mining.

These are the types of policies the Reagan administration would like debtor countries to adopt to qualify for fresh funds under the borrowing-and-growth strategy outlined by Treasury Secretary James A. Baker III last October.

But Febres Cordero's program is now in some jeopardy as a result of falling world oil prices. Oil, drawn from the jungle, is key to the Ecuadoran economy. In the past, Ecuador had been able to increase production to compensate for falling prices, but international markets are now glutted. The government estimates that the tumble in prices so far this year will produce a revenue shortfall of $700 million.

"Though things are hard, it isn't that we're doomed," remarked the 55-year-old Ecuadoran leader, who said he would try to steer a course between recession and inflation. To cover some of the unforeseen deficit, the government plans to increase such exports as shrimp, coffee and bananas and seek accelerated loan disbursements from the World Bank.