Newly released cabinet documents have shed light on Australia’s ill-advised decision to become involved in the Iraq war more than 20 years ago.

A dump of once-sealed documents from 2004 today reveal the Howard government was warned to prepare for the potential an Australian could be taken hostage as the war raged on in Iraq.

Australia committed troops to Iraq in 2003 in the US-led invasion based on wrong information, but it was not a “malicious” decision, former prime minister John Howard said.

The trove of records included papers from the powerful National Security Committee, with information on matters including Iraq, defence procurement, relations in the region and the threat of terrorism.

Among them is a warning letter from then-foreign minister Alexander Downer, detailing “contingency plans should an Australian fall victim to a hostage-taking incident”.

The plans were based around the belief the regime had weapons of mass destruction, which was disproved in January 2004.

Ahead of the cabinet papers release, Howard said the failure of US intelligence, which convinced Australia to take part, came as a blow.

“It was done in good faith, it was based on all the available intelligence and we found the plans, we found the programs to build them, but not the stockpiles,” Howard told reporters in December.

“We were wrong, in fact, but not maliciously.”

The Bush administration in the US conceded its pre-war justification for invasion in Iraq was unfounded in January 2004.

Australian cabinet documents are unsealed on January 1 after 20 years and shared publicly by the National Archives.