Senior Australian Labor politician Matthew Gardiner travels to Syria 'to fight against Isis'

Reports said the president of the party’s Northern Territory branch had gone to join Kurdish fighters

Screengrab from an ABC News report shows Matthew Gardiner speaking at a Labor event (ABC)

A senior politician in Australia’s opposition Labor party has travelled to Syria with the intent of joining Kurdish fighters in the war against Isis, it has been reported.

Matthew Gardiner was the president of the party’s Northern Territory branch and a high-profile figure in two of the state’s biggest labour unions – until he disappeared several weeks ago and his mobile phone went dead.

Now, the ABC has reported that Gardiner was among at least 90 Australians now thought to be fighting overseas either for or against the so-called “Islamic State”.

According to ABC, the 43-year-old was stationed as a combat engineer with the Australian Army in Somalia in the 1990s, prior to his career in politics.

The Australian Federal Police (AFP) confirmed to Guardian Australia and the ABC that the circumstances of Gardiner’s leaving the country were the subject of a police investigation, but refused to comment further on details.

A spokesperson for the Australian attorney general, George Brandis, told the ABC that regardless of which side Gardiner fought on, if he was found to have joined the conflict and then tried to return to Australia he would face “up to life in prison”.

“We know there are some Australians who think they've made the right choice in becoming involved in overseas conflicts, but that choice only adds to the suffering in Syria and Iraq and it's putting those Australians and others in mortal danger,” the spokesperson said.

The United Voices union told reporters that Gardiner had resigned prior to his disappearance, but he had remained president of the Northern Territory Labor branch until reports of his alleged travel to Syria emerged. He has now been stood down and had his party membership suspended.