AUGUSTA — Democratic gubernatorial hopeful Joseph E. Brennan charged Monday that Republican Gov. John R. McKernan is playing politics with the state budget in an attempt to cover up “the biggest fiscal mess in Maine history” until after the November election.

McKernan, meanwhile, stepped up his media campaign by releasing a new TV commercial that attacks Brennan’s record on fighting illegal drugs during his eight years as governor and four years as southern Maine’s congressman.

“The drug war was clearly not a priority for him,” the incumbent said of his challenger.

Brennan, echoing criticism voiced earlier this month by Democratic legislative leaders, noted that projections prepared by the GOP administration call for a disproportionately large share of the revenue growth expected this fiscal year to occur after the election. The state’s fiscal year runs from July 1 to June 30.

“Of the $190 million in new funds needed this year, only $15 million, or less than 8 percent, is projected to come in before the election, and $175 million, or over 92 percent, is projected to come in after the election,” he said in a prepared statement.

Brennan, who appeared at a news conference in Portland, accused McKernan of deflating the pre-election projections to make the state’s budget problems appear less serious than they actually are. Revenues for July, the first month of this fiscal year, were barely above the total for July 1989.

“To try to manipulate the figures and hide the real problems until after the election is a disservice to the people of Maine,” he said. “Whoever is elected the next governor will end up facing the biggest fiscal mess in Maine history.”

Brennan said that, if elected in November, he would call upon accountants and economists from private business and academia to volunteer to assess the state’s fiscal situation and “give the real facts to the Maine people.”

“The group will then be made permanent, a Council of Economic Advisors, to guard against this kind of mess ever happening again,” he said.

McKernan’s chief budget adviser said Brennan’s charge is “intellectually dishonest and totally ignores the makeup of revenue growth for fiscal 1991.”

Finance Commissioner H. Sawin Millett said the $190 million figure that Brennan cited is misleading because it excludes $41 million in income-tax overpayments that accumulated through early 1989 and was refunded to taxpayers through the overhaul of the income-tax system enacted last year.

Millett said that money is customarily counted as income-tax revenue for just-ended fiscal 1990, shrinking the amount of new revenue needed to fulfill projections this fiscal year to less than $150 million, and that Brennan has chosen “a new logic” to bolster his viewpoint.

Of that amount, Millett noted that more than $80 million will come from initiatives whose impact will not be felt until later in the year. They were part of a budget-balancing bill that was the focus of intense negotiations earlier this year between McKernan and Democrats who control the Legislature.

Those initiatives include a one-time tax-amnesty program that takes effect in November and is expected to raise $15 million, and a change in the deadline for employer-withheld income-tax payments that is expected to generate $12 million once it takes effect in January.

Some of the changes already have taken effect, but will have a delayed impact, Millett said.