Over the past five years, the United States approved for sale to Iraq $1.5 billion worth of computers, electronic equipment and machine tools that could be used in that country's programs to develop nuclear weapons, missiles and poison gas, according to government documents.

The list of sales includes computers that went to Iraq's Interior Ministry, its military college and research labs that are believed to be involved in missile, gas and nuclear programs. Other computers were sold to help Iraq analyze satellite photos. A steel-forging press was sold to the Ministry of Heavy Industries for use in Iraq's petroleum industry, but U.S. government officials said it also could be used by the military.

"It's quite shocking when you see the kinds of materials that were sent," said a congressional investigator looking into the government's policy on technology sales to Iraq.

The sales were the most visible manifestation of a Reagan and Bush administration tilt toward Iraq in its punishing war with Iran.

The tilt ended shortly before the Aug. 2 Iraqi invasion of Kuwait, although the Commerce Department unofficially began to slow down the process of issuing export licenses to Iraq last spring, officials said.

The officials added that 71 export applications, worth almost $30 million, were tied up by late July, when Secretary of State James A. Baker III asked Commerce Secretary Robert A. Mosbacher to impose more rigid controls on sales to Iraq. A few months earlier, administration sources said, the State Department had balked on imposing tighter controls.

Government documents show that the sales were approved by the Commerce, Defense, Energy and State departments and the intelligence agencies.

While former defense officials have said they tried to block some sales, the government documents show that the Pentagon declined to appeal differences with the Commerce Department to higher authorities in the administration. Paul Freedenberg, the former Commerce Department undersecretary in charge of export controls, said he recalls four cases in which the Defense Department objected, but all four sales went through because the Pentagon did not appeal them.

"It was U.S. policy to continue normal trade with Iraq," said Freedenberg.

"The State Department was eager to see that trade continue and improve. Overall, I had to follow the U.S. government guidelines."

Government documents show that total U.S. sales of high-technology goods surged in 1985 and 1986, reaching $780 million, but dropped down to $720 million over the four-year period from 1986 until the middle of this year.