The White House has decided to push hard for revisions in key portions of the Clean Air Act during the upcoming lame-duck session, including some of the same proposals it has been unable to steer through Congress for the past 18 months.

The decision, confirmed yesterday by a high administration official, surprised virtually all sides in the clean-air debate: industry lobbyists, environmentalists and House and Senate strategists. The issue was believed too complex and controversial to resolve in the rushed wind-up of the 97th Congress.

Nonetheless, a high administration official said yesterday that the White House will lobby for several changes in the act during the lame-duck session, including an extension of the current Dec. 31 deadline for all regions of the country to comply with national clean-air standards.

"The deadlines are definitely a priority," the official said. "Now it's a matter of deciding how much else we're going to bite off."

That decision will be made sometime after Election Day, according to several officials. Other possible priorities include a change in standards that protect already clean air and a relaxation of current auto emissions limits, the official said.

These are the revisions President Reagan had in mind in his recent televised speech, the officials said, when he voiced support for a clean-air act "which, while protecting the environment, will make it possible for industry to rebuild its productive base and create more jobs."

Environmentalists and industry lobbyists expressed skepticism about the prospects for administration-backed changes in the act since the House Energy and Commerce Committee refused to approve them in the regular session and the Senate Environment and Public Works Committee reported out a measure that is far more stringent than the administration wants.

The chief argument being advanced by the administration for extending the Dec. 31 deadline is that about a dozen states will be unable to meet it and that the federal government will be forced to impose sanctions that could cause "major economic problems."

The chief sanction is a ban on construction of certain plants in regions where air would remain more polluted after Dec. 31 than the national standards allow.

"It's an economic question, you could see some large-scale shutdowns if those deadlines aren't met," one administration official contended.

That prediction has been sharply disputed, however, by attorneys for the House and Senate committees handling the bill. Staffs of both panels concluded that the Environmental Protection Agency, which enforces the act, would not have to impose construction moratoriums for several months after the deadline.

It would take at least that long to collect data proving that the air in any region was too dirty to meet the act's standards, the attorneys said, and it could take even longer to enforce the ban.

"The sword of Damocles is not going to fall at 12:01 a.m. on Jan. 1," said an aide to the Senate Environment and Public Works staff. "There's no urgent and pressing need to extend the deadlines. Nobody seems worried about them except the administration, not even industry."

As such, advocates of a tough clean-air bill contend that the administration is invoking the deadline problem as an excuse to push for a softer act.

Funding for enforcement of the act technically ran out more than a year ago, and EPA has been paying for it under a different authorization, a situation that can continue into 1983 or until Congress reauthorizes the act, several officials said.