Blix spent three years searching for Iraqi chemical, biological and ballistic missiles as head of the U.N. Monitoring, Verification and Inspection Commission. He has been critical of the role played by the U.S. and British governments in Iraq, in interviews since his retirement on June 30.
"In Iraq, there was no sign of an immediate threat" from weapons of mass destruction, Blix told the Athens daily Kathimerini, in an interview published Sunday. "What worries me is the questionable honesty of a government that publicly presents certain arguments, but privately has different thoughts."
President Bush and British Prime Minister Tony Blair have come under increasing pressure to prove that Iraq had a weapons of mass destruction.
"The American government ... has the tendency to reach hasty conclusions," Blix said "I don't think anything will come to light in Iraq that will justify the invasion."
In the weeks before U.S. and British forces invaded Iraq, some U.S. officials strongly criticized Blix's reports to the Security Council for failing to support the Bush administration's contention that Saddam had an active illegal weapons programs.
Blix, whose remarks were published in Greek, was interviewed in Stockholm, Sweden.