President Reagan announced yesterday he would not press for legislation this year to speed the decontrol of natural gas, thereby dropping for the near future a major energy plank of his 1980 campaign platform.

White House Deputy Press Secretary Larry Speakes said the president, after extensive consultations with congressional leaders, had decided that any accelerated decontrol bill would "overload an already heavy legislative agenda."

The White House retreat represents tacit acknowledgement of the political cost of pushing election-year legislation that could double natural gas prices by 1985. Roughly half of the nation's homes are heated with natural gas.

Industry leaders, who had been waging an extensive lobbying campaign in support of accelerated decontrol for the past year, expressed their disappointment with the decision, in the words of H.E. Gene Wright, chairman of the Natural Gas Supply Association.

Consumer and labor groups were delighted with the anouncement, but cautioned that they think Reagan now will try to achieve through administrative action what he could not accomplish through the legislative process.

They noted that the Reagan appointee who now chairs the Federal Energy Regulatory Commission, C.M. (Mike) Butler, is preparing a proposal that would raise the average price of all gas by about a third.

"We've won the battle, but we haven't yet won the war," said Robert Brandon, director of the Citizens/Labor Energy Coalition, who claimed that Butler was prepared to "stretch the limits of the law" in finding ways to achieve higher gas prices administratively.

In making the announcement yesterday, Reagan stressed that natural gas decontrol "remains an essential component of a sound energy policy." Speakes did not address the issue of administrative decontrol.

Two leading congressional Democrats, Michigan's Rep. John D. Dingell, chairman of the Energy and Commerce Committee, and Illinois' Rep. Dan Rostenkowski, chairman of the Ways and Means Committee, already have introduced a resolution designed to warn the administration against any attempted "back-door decontrol" of natural gas prices by FERC.

Reagan's decision to drop accelerated decontrol legislation comes after repeated warnings by GOP leaders in both houses that no bill could be enacted unless it was accompanied by a windfall profits tax, which the president steadfastly opposes.

Congress partially decontrolled natural gas in 1978, establishing a phased schedule to get U.S. prices into line with the world price of oil by 1985. However, the schedule was thrown out of kilter by sharp increases in oil prices in 1979 and 1980, and the industry argues that unless new decontrol legislation is enacted now, there will be a sharp --and politically unacceptable--"fly-up" of natural gas prices in 1985, when controls are scheduled to be removed from all gas discovered after April 1977.