Saddam Hussein was no 'immediate threat'

Former Iraqi dictator Saddam Hussein was not an "immediate threat" but still had to be toppled, says a former Howard government defence minister.

As Australia weighs up the price of helping the US destroy the extremist Islamic State group in Iraq, Brendan Nelson has defended the Howard government's decision to follow the US into the middle eastern country in 2003.

He said based on what the government knew at the time, and not hindsight, it was the right thing to do.

"We knew Saddam Hussein had WMDs (weapons of mass destruction) and had used them ... we did not know if he still had them," Nelson, now director of the Australian War Memorial, said.

"Saddam Hussein in hindsight was not an immediate threat, but he was an inevitable one."