The veteran freelancer, who was compiling a report for SBS's Dateline program, was seized outside his Baghdad hotel about 5pm (AEST) on Saturday, SBS said.

"He was taken from outside his hotel in Baghdad and held for over 20 hours, during which time he was interrogated," SBS said.

Mr Martinkus had completed filming and was about to leave the country when he was detained.

"Martinkus has been released without harm and will be returning to Australia within the next few days," SBS said.

"In order not to compromise his safety and until more detailed information can be gathered SBS Television will not be commenting further on his situation at this stage."

Earlier, Foreign Minister Alexander Downer said the journalist had ignored advice not to travel to the part of Baghdad where he was seized.

"In this particular case, the journalist went out to investigate a story, I understand, and went to a part of Baghdad he was advised not to go to," Mr Downer told Melbourne radio 3AW.

"But he went there anyway ... he was detained but just for 24 hours and subsequently has been released."