Russian president Vladimir Putin says there is a "good chance of resolution" in Ukraine, rejecting Western condemnation of his country's role in the conflict.

"Today the situation [in Ukraine], in my view, has good chances for resolution, no matter how strange it may sound, but certain structures had been established on both sides that could handle the tasks they are facing better," Mr Putin told a select meeting of reporters on the side of the G20 summit in Brisbane.

Putin added that Kiev's decision to impose an economic blockade of eastern Ukraine was a "big mistake", but "not fatal".

The Russian president was the first leader to depart the summit, before the release of the official communique, saying he had a long flight to Russia and wanted to get some sleep.

"We need nine hours to fly from here to Vladivostok and another nine hours from Vladivostok to Moscow," he said.

"Then we need to get home and return to work on Monday. There's a need to sleep at least four to five hours."

He did, however, thank Prime Minister Tony Abbott for hosting the event and attended the annual forum's wrap-up lunch, praising the summit's "constructive atmosphere", despite the pressure put on him by Western leaders over the Ukraine crisis.

Speaking at a press conference broadcast on Russian television, Mr Putin said "some of our views do not coincide, but the discussions were complete, constructive and very helpful".

Mr Putin came under intense diplomatic pressure at the summit to cease supporting separatist rebels in Ukraine, where more than 4,000 people have been killed in the conflict.

European leaders in Brisbane warned Mr Putin risked more economic sanctions if he did not withdraw troops from the region.

Mr Putin's repeated denials of any involvement in an escalation of the separatist war did not spare him stinging rebukes from some leaders at the summit.

"I guess I'll shake your hand, but I have only one thing to say to you: you need to get out of Ukraine," Canadian prime minister Stephen Harper told Mr Putin on Saturday.

At his media conference, Mr Putin also said G20 leaders discussed reform of global energy institutions.

"The geography (of oil exporters) is changing to a certain extent, structural changes in global energy are taking place and, of course, one requires new institutions regulating this very important area," he said.

Reuters/AFP