BRISBANE Australia (Reuters) - Russian President Vladimir Putin said on Sunday that there was a "good chance of resolution" in the Ukraine conflict, rejecting Western condemnation of Russia's role in the southeast of the country.

"Today the situation (on 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," 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 leader left Australia on Sunday before the formal end of the two-day G20 summit. Putin said he was leaving before the release of the official communique because of the long flight to Russia and he wanted to get some sleep.

Putin come under intense diplomatic pressure at the summit to cease supporting separatist rebels in Ukraine, where a conflict has killed more than 4,000 people this year.

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

Putin's repeated denials of any involvement in an escalation of the separatist war has not spared him stinging rebukes from some leaders at the two-day 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 Putin on Saturday.

At his media conference on Sunday, 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," Putin said.

(Reporting By Alexei Anishchuk; Editing by John Mair and Michael Perry)