NEW YORK (AP) _ The credit-starved New York Post could suspend publication next week unless its unions agree to a one-month pay cut of 20 percent, its owner said.

The nation's oldest continuously published daily, known for its blaring headlines and feisty reporting, has for years been struggling for profitability in a highly competitive market.

Owner Peter Kalikow put the tabloid up for sale Friday, saying it could close as soon as Monday if the unions don't agree to the cutbacks.

''If I could somehow get a temporary wage cut, as well as other revenue enhancements, basically we might be able to keep the paper going,'' he said in today's New York Times. ''This would allow us a four-week period in which to identify one of the buyers.''

The newsstand price of the tabloid will increase a dime to 50 cents on Monday if the newspaper publishes, he said.

''I see that this is the only way to keep our jobs,'' said George McDonald, president of an umbrella group for eight Post unions representing 716 workers.

The crisis comes just weeks after the sale of the Daily News to Mortimer Zuckerman stabilized the financial picture for that competing tabloid.

Four unions agreed to Kalikow's proposal late Friday night. The others have until 6 p.m. Sunday to decide, said McDonald, president of the Allied Printing Trades Council.

Martin McLaughlin, a spokesman for Kalikow, said the announcement was prompted when Post lender Bankers Trust cut off credit. Bankers Trust spokesman Tom Parisi declined to comment on the decision.

Kalikow has ''four or five people interested in buying the paper,'' McLaughlin said.

Some of the deals would involve Kalikow keeping a percentage, while others would involve buying the tabloid outright, McLaughlin said.

Kalikow bought the Post for $37 million in 1988 from media baron Rupert Murdoch.

Two years later, Kalikow asked workers to switch to a four-day week - and take a 20 percent pay cut - to keep the Post alive.

About half of that pay cut was restored to employees in June 1991, and Kalikow has maintained since then that the paper was turning a profit.

The paper's weekday circulation has tumbled to 438,000, down from an all- time high of nearly 1 million in the early 1980s. The Post has no Sunday edition.