The Taliban has released a video showing an Australian hostage asking US President-elect Donald Trump to arrange a prisoner exchange to secure his freedom.

Key points: Australian Timothy Weeks and American Kevin King were teachers in Kabul

Australian Timothy Weeks and American Kevin King were teachers in Kabul It is the first time they have been seen since abduction in last August

It is the first time they have been seen since abduction in last August US forces conducted an unsuccessful rescue mission in last September

Australian Timothy Weeks and fellow hostage American Kevin King were teachers at the American University of Afghanistan in the capital Kabul, when they were kidnapped near their university campus in August last year.

It is the first time the pair has been seen since their abduction.

In a statement, the university's acting president David Sedney said seeing the video "saddened and pained" their colleagues.

"These innocent people have done nothing to harm anyone and need to be reunited with their family, friends and colleagues," Mr Sedney said.

US forces conducted a rescue mission for the two men in September, but they were not at the location of the raid.

Hostage negotiation expert Neil Fergus from security contractor Intelligent Risks said that the video is evidence of proof the hostages are alive.

"The kidnapper is no doubt keen to put some pressure on for governments of these two individuals," Mr Fergus said.

"What we say is proof of life is being given and that's the good news, that they are both still alive and trying to get some progress made in terms of the demands and the negotiations."

Mr Fergus said it is unlikely the video is a tactic to pressure incoming President Donald Trump, but he said the video will pose a problem for both the US and Australian governments.

"We're not dealing with one of the criminal cartels, or criminal groups that are engaged in these kidnappings, we're dealing with a group which is proscribed on a number of international lists as a terrorist group," he said.

"Naturally the Australian Government and the US Government will not negotiate with a terrorist group, so it's a difficult situation."

Mr Sedney said in Afghanistan all efforts were being made to secure their safe release.

"We will not give up, we will not stop pressing all involved to do all they can," he said.

"Our thoughts and prayers are with you constantly. We will not rest until you are back safely with us."

Second video of abducted Australian emerges

Meanwhile another video has also surfaced online, purporting to show an Australian citizen abducted in Yemen.

In the footage, which first appeared on Tuesday, the man gave his name as Craig McAllister while a rifle was pointed at his head.

He said his captors would kill him if their demands were not met, but he did not say who his captors were or specify their demands.

Australia's Department of Foreign Affairs and Trade said it was providing consular assistance to the family of an Australian man kidnapped in Yemen.

Yemeni security officials, speaking on the condition of anonymity, said Mr McAllister was taken in early October in the capital, Sanaa, but his captors remained unknown.

ABC/AP