The Reagan administration, which contends its plan to increase funding for the International Monetary Fund is essential to avoid a worldwide financial crisis, is having more difficulty than it expected in convincing the House of Representatives of this.

Opposition to the bill to boost the U.S. contribution to the international financial rescue agency comes from both sides of the aisle. Some is ideological, some is pragmatic. As one aide to the House leadership lamented, a legislator can expect very little political gain from a vote for the IMF.

Clouding the issue for conservatives, moderates and liberals is the suspicion that the increase in the International Monetary Fund's resources is nothing more than assistance for giant multinational banks in the United States, Europe and Japan that made too many imprudent loans to Third World countries.

Although the Senate approved the legislation handily last month, Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) said last week that he could count no more than 130 of the 218 votes the bill needs to pass the House. O'Neill supports the administration bill. Other House leaders complain that the White House has not made enough of an effort to convince Republicans of the necessity for the bill.

The IMF has played a key role in putting together new loan packages for nations such as Brazil and Mexico after they borrowed heavily from banks and others and then found themselves strapped for cash when the industrialized world plunged into a recession in 1981 and cut back their imports from developing countries.

Without the IMF--which made loans to the debtor nations and in return required them to take steps to put themselves back on the road to economic health--some of these countries might have had to default on their debts, supporters say, with grave consequences for international finance and trade and, ultimately, the health of the world economy.

But the IMF, which has 146 member nations, is close to having lent out all its funds and needs more. The major nations of the world have agreed to boost the IMF's resources to enable it to deal with future cash crises.

"I'm not Chicken Little," Treasury Secretary Donald Regan told business leaders last week while asking them to put pressure on legislators to support the $8.1 billion U.S. share of a total $41.8 billion IMF funding increase. "But I'd hate to think of the consequences" if the House fails to support the increase.

Many conservatives do not believe claims by Regan and others, such as Federal Reserve Board Chairman Paul A. Volcker, that the health of the international system is at stake. They argue that the system can function without the IMF, that banks will find ways to work out the problems of indebted countries, just as they do for troubled companies. Some think the consequences of a debtor-nation default would not be disastrous.

Furthermore, according to conservatives such as Rep. Jack Kemp (R-N.Y.) and Rep. Bill McCollum (R-Fla.), the IMF has gold resources it can use if it has to and that the IMF can borrow funds from private markets--much as its sister organization the World Bank does.

Many liberals think the Reagan administration is too lavish with its foreign spending and too niggardly domestically. While many of them probably can be convinced to vote for the IMF increase, it may be only in return for an administration pledge to lobby for a $23 billion housing bill that passed the House but is languishing in the Senate.

Reagan "can't sustain being Adam Smith domestically and Franklin Roosevelt internationally," said Rep. Barney Frank (D-Mass.).

The banks have few friends on either side of the aisle. Although the they stretched out repayment for overburdened borrowers like Mexico and Brazil and lent them new funds in concert with the IMF, the banks did so at enormous profit to themselves. The renegotiated loans carry higher interest rates, and the banks collected handsome fees from the countries in return for renegotiating the terms.

Rep. Charles E. Schumer (D-N.Y.), among others, thinks the banks should reduce the rates on loans to troubled Third World countries before the United States jumps in with an IMF funding increase.

Regan, who is spearheading the administration's efforts to pass the IMF bill, counters that the developing countries got the low-rate loans when they were perceived to be impeccable credit risks. Now, he said, loans to those countries are riskier, so it is only fair for banks to make provision for that risk by charging higher rates.

Even many bankers swallow hard at that line of reasoning. The head of Latin American lending at a major U.S. bank--who was not on the committee that negotiated the new loan packages with debtor countries last winter--said that when companies get into trouble, banks cut their loan charges. He said banks should do the same for troubled countries.

"I'm making a lot more money on those loans," the banker said. "But the underlying assets are a lot shakier as a result."

Even Volcker has told Congress he has severe doubts about the wisdom of some of the renegotiated bank debts. But both Volcker and Regan say that it is essential to keep the big banks lending to the debtor nations until those countries can get back on their feet. The only way to keep them making loans is for the International Monetary Fund to be involved.

The IMF makes loans of its own to these countries, and in return demands that the countries take unpalatable steps to put their economic houses in order: reducing subsidies to consumers and businesses, cutting back government spending, reducing inflation and, often, sharply cutting the value of their currencies in order to run a trade surplus.

It is only with the IMF imprimatur that banks can be induced to continue lending, supporters of the IMF legislation argue. No bank is powerful enough to make a country take belt-tightening steps. Only a multinational institution like the IMF can do that.

Unless banks keep lending, the countries will have to cut back even more than they already have on their imports, resulting in a serious impact on U.S. jobs. About 40 percent of U.S. exports go to developing countries. Mexico is the nation's third largest trading partner.

"It may be a bank bail-out in a sense," said one government official. "By keeping the world economy afloat we probably make sure the banks' loans are in better shape. But the consequences of cutting off IMF funding merely to punish the banks is self-destructive."

Although nearly everyone agrees that the key to the debt crisis is a strong recovery in the industrialized nations that boosts demand for the commodity exports of the developing countries, many legislators worry that the IMF programs will keep the debtor nations from growing.

"The IMF is not helping thse countries to grow when they impose tax policies" that squeeze businesses and industries in order to increase government revenues and reduce the government's need to borrow, according to Kemp. He said the IMF imposed huge tax increases on Mexico that will hurt the country, not help it.

"It will be a long hard fight," predicted one legislator. "It will take direct involvement by the White House."

Rep. Fernand St Germaine (D-R.I.), chairman of the House Banking Committee, which reported the bill to the floor, said he thinks that "eventually we'll have legislation," but he is circumspect about saying when the bill can come to the floor for a vote.

"Despite their legitimate misgivings about the bill and the IMF, most members will recognize that in the short run they have no alternative but to boost the IMF's funding. And when it gets down to it, the House this year has always voted for things it had to," said one key congressional aide.