An attorney for Rep. George V. Hansen (R-Idaho) asked a U.S. District Court judge yesterday to throw out an indictment charging Hansen with filing false financial disclosure statements, claiming that he was being singled out by the executive branch as the one member of Congress "they want to silence."

"He is the most outspoken critic in the House of the administration," said lawyer Roy Cohn, in asking Judge Joyce Hens Green to dismiss the charges against the seven-term member of Congress. "He's probably the most outspoken member of the House of Representatives."

The indictment charges that the 52-year-old Hansen neglected to report on disclosure forms four financial transactions, including two with Texas billionaire Nelson Bunker Hunt. One was a profit of $87,475 made by Hansen and his wife on the purchase and sale of 125 contracts to buy silver worth nearly $4 million in 1979. Another was a $50,000 personal bank loan made to the Hansens and guaranteed by Hunt.

Hansen sat at the defendant's table yesterday. Judge Green had previously rejected his request that he be excused, because of the press of congressional business, from attending hearings on the case.

Cohn suggested yesterday that Hansen had been "singled out" as the only member of Congress to be prosecuted for filing false information under the 1978 Ethics in Government Act.

Hansen has been a frequent critic of the Internal Revenue Service, the Justice Department and other agencies.

Cohn said that Congress, in passing the law, had specifically rejected the idea of including a criminal penalty for making a false statement, providing instead for a $5,000 civil penalty.

According to Cohn, some member of the House clerk's office included a warning on the bottom of the financial disclosure statement that false information is a criminal offense, based on a federal statute that punishes any false statements made to the government. It is that general federal statute under which Hansen is being prosecuted.

"I don't think any of us knows which clerk put it there," Cohn said. "The act itself provides for a civil penalty."

Comparing the disclosure form to a legislative debate, Cohn argued that Hansen is protected by the Constitution, which says members of Congress may not be arrested or questioned for any speech or debate in the House or Senate.

But Assistant U.S. Attorney Reid Weingarten told the judge that the disclosure form is not like a legislative debate and that Congress, in passing the financial disclosure law, specifically allowed for intrusion by the executive branch.

If Congress had intended to exempt its members from criminal sanctions, he argued, it would have done so.

Hansen could face up to five years in jail or up to a $10,000 fine, or both, on each of the four charges against him.

Green said she would rule on Hansen's request in about a week. His trial is set for June 20.