Complaints from upset Utahns started ringing into congressional offices Tuesday just as soon as word spread that a commission had recommended a 50 percent pay increase for members of Congress.

That prompted two members of Utah's congressional delegation to issue quick statements that at least partially condemned the planned pay hikes - and left the other three congressmen considering whether they should, too.Rep. Howard C. Nielson, R-Utah, said he supports a pay increase but not one as large as recommended by the Commission on Executive, Legislative and Judicial Salaries. Sen. Orrin Hatch, R-Utah, said he would vote against the pay increase - but it could be implemented without a vote in Congress.

The committee recommended raising pay for congressmen from $89,500 a year to $135,000 - as long as Congress bans honoraria, the outside pay they may receive for making speeches.

Critics call honoraria a conflict of interest because speeches are often made to groups interested in influencing a legislator's vote.

The commission's recommendation goes to President Reagan, who may alter or accept it. Reagan will send his final pay recommendation to Congress Jan. 9. It will become law unless Congress votes within 30 days to overturn it - a controversial procedure that was appealed to the U.S. Supreme Court two years ago but upheld.

Nielson said the proposed pay increase is too high.

"I support the elimination of honoraria," Nielson said. "And I support the idea of increasing salaries to compensate for the loss of those honoraria. But I will do everything I can to block any attempt to increase salaries beyond that point."

House members are now allowed to keep $26,850 in honoraria, or 30 percent of their House income. Senators are allowed to keep $35,850, or 40 percent of their Senate pay. They may earn more in honoraria but must donate it to charity.

But Nielson said he would support increasing pay by only the $26,850 that House members may now earn from honoraria. "The House ceiling for honoraria of 30 percent is more than high enough," he said.

A press release from Nielson added in partisan wording, "Nielson has a well-established record of vigorously opposing salary increases. During the last session he fought efforts to raise congressional pay. And after the pay raise was pushed through by Democrats, he donated the raise he received to universities and other charities."

Two years ago, the Senate voted to turn down a proposed increase. But when the House did not vote on the matter within the required 30 days, it automatically took effect for both houses.

About that procedure, David Keating, director of the National Taxpayers Union, said Tuesday, "That way our clever politicians can pocket a big pay raise and claim they had nothing to do with it. This scheme was designed to fool the voters and enrich the Congress."

Hatch said, through his assistant press secretary, Jeanne Lopatto, that he would vote against a pay increase as he has in the past. Hatch is among the leading senators in honoraria earnings. He earned $79,926 in honoraria last year but donated $48,889 of it to charity.

Art Kingdom, press secretary for Rep. Wayne Owens, D-Utah, said Owens refused to take a pay increase that Congress received two years ago - partially because he had attacked his opponent that year, Salt Lake County Commissioner Tom Shimizu, for giving himself a large raise.

Owens gave the increased amount he received to funds for 15 scholarships for Utah students.

According to Kingdom, Owens said in the campaign this year that he intended to take his full $89,500 salary but has not said whether he favors the proposed pay hike.

Owens himself was unavailable for comment. He is in Iraq on a two-week fact-finding tour for his assignment on the House Foreign Affairs Committee.

Jeff Bingham, administrative assistant for Sen. Jake Garn, said Garn is considering the pay raise and will likely announce a position on it soon.

Aides for Rep. Jim Hansen, R-Utah, said they were unsure of Hansen's stand on the issue. As of press time, Hansen's office had issued no further statement. Some of the reasons members of Congress often list for wanting a raise include that they must maintain a house and car both in Washington and their home district; the cost of living is extremely high in Washington; and that higher pay would no longer force them to take honoraria to make ends meet.

They also say that if pay is not sufficiently high, only the wealthy or unscrupulous would be willing to run for office.

Lloyd Cutler, chairman of the commission on salaries, also said that while the pay of most American workers has slightly outpaced inflation over the past two decades, average top government salaries have eroded by 35 percent compared to inflation.

Critics opposing the pay hikes say they are too large and that congressional salaries are already much larger than what average Americans earn.