The National Endownment for the Humanities has frozen grants for the next few days in response to a Senate subcommittee recommendation to cut back funding for Humanities and its sister agency, the National Endownment for the Arts, for the current fiscal year 1981.

"We heard late Thursday afternoon," said NEH public relations officer Barry Wanger yesterday. "Joe [Duffey, the NEH chairman] immediately told our people not to send out any more money."

The humanities endownment would be cut back a little over 7 percent, from $151.3 million to $140 million, and the arts endownment would be cut back 6 percent, from $159 million to about $150 million, according to Glenn Gershaneck, press secretary to Sen. Robert T. Stafford (R-Vt.), chairman of the Senate subcommittee on education, arts and humanities. Both recisions were recommended by Stafford's subcommittee, which was under orders from the full Senate Committee on Labor and Human Resources to find places to cut. The full committee will make a total of $1.8 billion in cuts to accommodate President Reagan's revised fiscal 1981 budget, which the House and Senate recently agreed upon. The full committee and then the full Senate must approve the recommended cuts in NEA and NEH. Then the House must approve them.

The NEH was ready to send out notification of 300 to 400 new grant awards, according to chairman Duffey, before it decided to hold them back.

"I think 70 percent of our funds have been spent, but I'm not sure," said Duffey. "So, we're holding everything for about three days. It's just to hold the flow and think about alternatives. A lot of things have to happen before we get cut."

The NEA, however does not plan to freeze funds immediately."If we froze our grants, there'd be a lot of people who wouldn't get money who need it now," said NEA chairman Livingston Biddle, who added, "Certainly we're not going to give out a lot more grants. But we're not going to slow down the process."

The NEA just finished a meeting with the National Council on the Arts, an advisory body to the NEA which must approve grants. "But [the grants] don't rush out the next week," said Biddle. "They get checked and rechecked and have to go to a lawyer. They have to be verified by program people. It can take six weeks, even longer."

This recommended cutback in fiscal 1981 funds is the second blow for the endownments, both of which face 50-percent cuts in funds in the proposed Reagan budget for fiscal 1982.

Talk of the current-year cuts came up yesterday morning as NEH officials testified at a hearing held by the House appropriations subcommittee on the interior. Rep. Sidney Yates (D-Ill.), chairman of the subcommittee and a strong supporter of the endowments, said he'd heard a rumor of the fiscal 1981 cuts. "I don't see how they could," he said of the Senate, after the hearing. "There are only three months left in fiscal 1981." (Fiscal 1981 ends September 30.)

Duffey said that if cuts were approved for the current fiscal year, those prospective grantees who will be approved at the fourth National Council meeting "are the ones who will be primarily affected. Elementary and secondary cirriculum development grants, state committees, some fellowship programs, scholarly conferences would be among those affected."

NEA chairman Biddle said that 30 to 35 percent of his agency's budget is already spent. Grants to major institutions -- major theaters, dance companies, museums -- as well as to state arts councils are the ones that are usually considered in the latter part of the fiscal year, he said. But these will not be more severely affected than other projects, according to Biddle, who said the agency will look at its different programs and see how much money has already been distributed. "It's going to be very complicated and there may be some injustices," he said, "but we'll try to be as fair as possible."