Australian prime minister Tony Abbott has declined to rule out military involvement in northern Iraq, saying he was not prepared to stand aside in the face of a potential genocide.

Speaking after a day of high-level intelligence briefings with British officials in London, Abbott described the unfolding atrocity in northern Iraq as a "humanitarian catastrophe" and said Australia would provide humanitarian aid to Yazidi refugees besieged by Islamic State (Isis) forces on Mount Sinjar in northern Iraq.

Abbott said: "As President Obama has said, it is a potential genocide and no one wants to stand aside in the face of a potential genocide."

Asked in a press conference in central London whether he would rule out Australian military involvement in the deepening crisis, the Liberal leader said: "We certainly don't rule that out. We are talking to our partners – our partners in this instance are certainly much wider than simply the US and UK – about what we can usefully do to help, but what I want to stress is this is a humanitarian cause.

"Protecting people from murder at the hands of [Isis] terrorists is a humanitarian cause. Trying to ensure that people are not exposed to terrorists who have been crucifying, summarily executing, decapitating, people who have been dealing in a hideous way with women and children – this is a humanitarian cause and Australia has a long and proud tradition of assisting people in need."

Earlier on Tuesday, Abbott said "at this stage" Canberra was only preparing to be involved in a humanitarian mission to help ensure that tens of thousands of refugees in Iraq were not "exposed to the murderous zealotry of the Islamic State".

Abbott spoke by telephone with David Cameron on the grave situation in Iraq earlier on Tuesday, when he also held meetings with the foreign secretary Philip Hammond, defence secretary Michael Fallon and Jon Day, chairman of the joint intelligence committee. The Australian leader was also given a high-level intelligence briefing at Thames House, the home of MI5.

Pressed on the potential return of military forces in Iraq, Abbott was keen to contrast the present situation with the 2003 invasion of Iraq led by the US and UK. "There is a world of difference between getting involved to prevent genocide and the kind of involvement we've seen in recent years by western forces in the Middle East. There's just a world of difference and no-one should conflate the two," he said.

It is understood that Canberra will deploy Hercules planes in a humanitarian airdrop to Mount Sinjar by the end of the week. British forces successfully dropped water and rechargeable solar lanterns to the besieged Yazidi refugees earlier on Tuesday.

As Abbott said discussions would continue over what more Australia could do to provide relief in northern Iraq, the Australian leader said the world should be sceptical of Russia's pledge to send a humanitarian convoy to eastern Ukraine.

"I think we should be sceptical of Russia's intentions because plainly Russia has been stirring up a world of trouble in Eastern Ukraine for many months now," he said.

"All of us are in favour of humanitarian assistance but no one wants to see what is effectively an invasion under cover of a humanitarian convoy. If it really is a humanitarian convoy the Russians plainly need to talk to the Ukrainians because it is Ukrainian territory that this convoy is supposedly bound for, and work out an acceptable arrangement with the Ukrainian government."