House Democrats as expected yesterday formally approved a resolution opposing President Carter's plan to decontrol domestic oil prices. Just as predictably, the White House fired back with a statement calling the action "contrary to the best interests of this country."

The House Democratic Caucus capped three days of debate by voting 138 to 69 for the resolution, which says it is Democratic policy ot extend controls. Carter has ordered a gradual lifting of the controls beginning June 1, until the end of September 1981 when, under existing law, all controls are to end.

During the debate, the Democrats strongly attacked the president's plan as a bonanza for the oil companies and a burden for consumers that would produce neither conservation nor much new oil.

The action has no legislative force, but it was clearly a slap at Carter and a reflection of strong and bitter reactions by constituents to gasoline shortages, rising prices and oil company profits. Rep. Andrew Maguire (D-N.J.) said he received 14,000 letters on energy issues recently, and other members of Congress have reported heavy mail questioning the reasons for the shortages, high prices and the oil industry's profits.

After the vote, 62 Democrats who voted for the resolution signed a letter to Carter to delay decontrol "at least until the House and Senate have the opportunity to act on oil pricing policies."

The reaction from the White House was a swift rejection of that request.

Approval of the resolution, presidential press secretary Jody Powell said, "is a politically attractive, nonanswer to our energy problems. It will not make them [the problems] better, it will make them worse. Simply voicing your determination not to face facts does not change the facts, nor does it make the problems go away."

But Powell, reflecting the optimistic sentiment of White House aides, said there is " a very good chance the House will act in a more responsible manner" than the Democratic caucus by rejecting legislation to extend controls.

As he has been doing for several days, Powell also accused the House Democrats of blaming Carter for an energy situation that the White House argues has resuled from congressional inaction on administration energy proposals.

"This idea of holding the president accountable for the actions of the Congress or a group in the Congress is absurd," he said.

The politically awkward position the vote placed Carter in was illustrated when a leader of the opposition, House Minority Leader John J. Rhodes (R-Ariz.), criticized the House Democrats in much the same way the White House has. The caucus vote, Rhodes said, "is another example of their failure to understand what is really at stake here. The bottom line is supply, and their tactics do not address that question."

The split between the president and members of his own party on the decontrol issue is likely to come up today when Carter speaks and answers questions at a meeting of the Democratic National Committee.

In other energy developments yesterday:

Barry Bosworth, director of the Council on Wage and Price Stability, said service station dealers appear to be "taking advantage" of fears about gasoline supplies by rapidly increasing their prices. Bosworth said retail gasoline price increases are about 25 percent higher than would be expected from increases in crude oil prices. His charge was denied by the National Council of Petroleum Retailers.

White House officials said the president was dispatching a team of administration officials to Kansas City today to meet with Midwest governors and discuss diesel fuel supplies, especially for farmers.

The letter sent to the White House by the 62 Democrats said the caucus vote was "in keeping with a growing public sentiment for restraints on rapidly escalating energy prices."

Rep. Toby Moffett (D-Conn.), author of the resolution, said, "the next move" is up to the president, to change his decontrol decision before June 1.

Moffett said if the president doesn't change his mind he will go ahead with an attempt to attach an amendment extending controls to a Department of Energy authorization bill now moving through the House.

The bill is expected to come out of the Commerce Committee soon, but must also be reported by the Interior and the Science and Technology committees, which could delay its consideration by a couple of months.

Moffett also said the focus now falls on Republicans, whom he acknowledged must supply 30 to 40 votes for the extension of controls to pass the House.

Minority Leader Rhodes said Republicans were taking a head count on decontrol, but Minority Whip Robert Michel (R-III.) said, "I don't think our members will vote for decontrol unless it means more production."

Rhodes said the Republicans would vote for a stronger "windfall profits" tax than President Carter wants, but would insist on a plowback provision to get more production.

Republicans also announced they are introducing a resolution of inquiry to get exact figures on oil shortages, demand, reserves, methods of allocation, withholding of supplies and movement of oil to foreign countries.

If passed by the House such a resolution must be answered by the administration in 15 days. It was last used in the 1970s to seek answers about U.S. troops in Cambodia.