Prime Minister Tony Abbott has called Russia a "bully" and demanded it stops "interfering" in Ukraine.

Mr Abbott's strongest comments on Russia to date came while he was in Ottawa, and followed Canadian prime minister Stephen Harper's criticisms of president Vladimir Putin.

Mr Harper described the Russian president as an "extreme nationalist" and "imperialist" who believes he has the "right and ability" to "invade" other countries.

"We're not at Hitleresque proportions but this is really disconcerting," Mr Harper told Canada's Global News. "This is a major power threatening global peace and security."

Mr Abbott backed the Canadian prime minister's comments.

"They're very forthright remarks and I think that they're perfectly appropriate remarks for the Canadian prime minister to make," Mr Abbott said.

Sorry, this video has expired Tony Abbott backs Canadian prime minister, tells Russia to stop bullying Ukraine ( James Glenday )

"Canada probably has more involvement in the affairs of Europe than Australia often does, but nevertheless let's not minimise the affront to international stability and the affront to the ordinary norms of behaviour between nations which Russia has been responsible for.

"I mean it's bitten off the Crimea," Mr Abbott said. "It's obviously interfering in Ukraine and this should stop. This should stop. No country has a right to bully another country just because it can."

The US and its allies excluded Russia from G8 talks - currently the G7 - after Moscow annexed Crimea.

Last week, the Group of Seven leading industrialised nations met for the first time without Russia in 17 years.

On Friday Mr Abbott was asked whether Mr Putin would still be invited to the G20 summit which will be held in Brisbane later this year.

Mr Abbott indicated he expected Mr Putin would be attending the November conference.

"At this point in time I'm expecting Russia to be well and truly part of the G20 in November," Mr Abbott said on Friday in Paris.

He said the G20's focus was economics, in contrast to the G7's emphasis on security.

"I can understand why the G7 leaders were reluctant to sit down with president Putin at this time," he said.

"But when it comes to the prosperity of the world, when it comes to the management of international finances, when it comes to harmonisation of taxation rules, when it comes to trying to promote global growth, I think it is best if we can include Russia."

Visit highlights ties with Canada and PM Stephen Harper

Mr Abbott underlined the importance of Canada's security and economic ties with Australia during his visit to Ottawa.

His meeting with Mr Harper today is expected to be a warm affair, with Mr Abbott heaping praise on the Canadian leader.

"He has been regarded as something of a beacon to centre-right parties around the world and certainly I have regarded Stephen Harper as an exemplar of a contemporary centre-right prime minister," he said.

On Sunday Mr Abbott met Canadian schoolchildren as he toured the nation's war museum, which has agreed to swap exhibits with the Australian War Memorial in Canberra.

Monday (local time) will be a day of formalities, with Mr Abbott and Mr Harper due to talk trade and security issues in their first full bilateral meeting.

A round table meeting will bring together business leaders from Australia and Canada and Mr Abbott will also call on the governor-general.

After a formal dinner in his honour the Prime Minister then flies to New York for the next stage of his trip.