Northern Virginia Democratic congressional candidate Ira M. Lechner charged yesterday that his Republican opponent, Rep. Frank R. Wolf, deliberately distorted his own voting record on federal pay and cost-of-living adjustments during a recent radio debate.

The 48-year-old former Arlington state legislator accused Wolf of trying to "rewrite the documented record" by denying in a debate broadcast Wednesday on WMAL-AM radio that he had voted to cap or change cost-of-living adjustments for retired federal workers from twice a year to once a year.

Last year as part of the administration's budget, Wolf voted on the House floor to change cost-of-living adjustments for federal retirees from twice to once a year. Last May, he voted for a budget proposal that would have completely eliminated 1983 cost-of-living increases for retired and active federal workers.

"I am going to say to Frank Wolf in the very next debate, 'Frank, if you're going to break your promises to people, just be candid about it,' " said Lechner during a press conference at Washington's Sheraton-Carlton Hotel. The press conference was attended by officials of federal employe unions who are backing the candidacy of Lechner, a Washington labor lawyer.

During Wednesday's debate, Wolf repeatedly denied that he voted to change or cap twice-yearly cost-of-living adjustments and accused Lechner of "distorting the facts" by saying that he had. "I did not vote to cap COLA cost-of-living adjustments or to change it," Wolf said.

Wolf again denied yesterday that he had voted against the interests of federal workers on these issues. He said the federal employe votes Lechner is questioning were part of larger pieces of legislation that he said he felt compelled to support.

"It's easy and misleading to take a piece of legislation and months later say what it means and completely ignore the circumstances of the time," said Wolf. "It's typical of my opponent's selective brand of researching. My record is very clear."

Issues affecting federal workers are particularly sensitive among Wolf's constituents, an estimated 40 percent of whom are active or retired government workers or are closely related to someone who is.

During campaign appearances two years ago Wolf, a conservative lawyer-lobbyist who swept to victory on President Reagan's coattails, promised repeatedly to support semiannual cost-of-living adjustments for his district's 23,000 retired federal workers who receive pensions, and to work hard for federal employes, more of whom live in his district than any other in the country.

In 1981, shortly after he took office, Wolf voted several times for administration-backed proposals to eliminate semiannual pension adjustments, a move that angered leaders of employe unions.

On June 25, 1981, Wolf voted against an amendment called the Bolling Rule that would have assured separate votes on six budget questions, including a provision to reduce cost-of-living adjustments for retirees from twice to once a year.

The rule was defeated. That meant that votes for or against the controversial adjustment were not individually recorded, because the issue was included instead in the larger budget package.

The next day, Wolf voted for the administration's budget package, which not only reduced cost-of-living adjustments but also contained a 4.8 percent pay cap for federal workers.

Wolf said yesterday that he voted against the Bolling Rule because it was a proposal by Democrats who were "trying to confuse and defeat" Reagan's budget package.

He voted for the budget, which reduced cost-of-living adjustments to once a year, because "it was a vote on the entire budget and brought down inflation."

On May 25, 1982, Wolf voted for a budget amendment proposed by California Republican Rep. John H. Rousselot that would have eliminated 1983 pay raises and cost-of-living adjustments for all active and retired federal workers.

During Wednesday's debate, Wolf did not explain his vote for the Rousselot amendment.

In a recent interview, however, Wolf described his support for it as "purely a symbolic vote. Everyone knew it didn't have the opportunity of passing. There are a lot of things like that in Congress. Symbolism in government and politics are extremely important."