BRISBANE: A weary Russian President Vladimir Putin on Sunday shrugged off a new barrage of Western fire over Ukraine at a G20 summit where the world’s most powerful leaders vowed to heat up the cooling global economy.

Host Tony Abbott insisted that everyone including Putin — who left the Brisbane summit early — was on board the G20 campaign to enact reforms that could infuse more than two trillion dollars into the world economy.

“I’m happy to be on a unity ticket with Vladimir Putin on that subject,” the Australian prime minister told a news conference after the two-day talks, during which the two leaders put aside days of sniping to share a photograph with cuddly koalas.

Nevertheless, Abbott insisted that he had had “very robust” discussions with Putin in recent days and described the July downing of a Malaysia Airlines plane over Ukraine as “one of the most terrible atrocities of recent times”.

Putin flew out of Brisbane shortly before the summit formally ended, but denied any snub to Abbott, saying it would take 18 hours to fly home via Vladivostok in Russia’s far east.

“Then we need to get home and return to work on Monday. There’s a need to sleep at least four to five hours,” said Putin, a judo black belt who prides himself on his stamina.

And the Russian strongman played down the testy exchanges seen in Brisbane, when at one point Canada’s leader expressed reluctance to shake his hand.

In general at the G20, Putin said, “some of our views do not coincide, but the discussions were complete, constructive and very helpful”.

The G20 leaders backed efforts to close loopholes between different tax regimes that allow some multinationals to get away with paying only a pittance on their profits.

Luxembourg is accused of having connived with such companies to the detriment of their home countries’ treasuries for years when Jean-Claude Juncker, now the European Commission president, was its prime minister.

The G20 endorsed a “common reporting standard” so that companies cannot arbitrage differences between tax regimes, stressing: “Profits should be taxed where economic activities deriving the profits are performed and where value is created.”

The Financial Transparency Coalition, a campaign group, welcomed the G20’s emphasis on “the ravaging effects tax evasion, avoidance and money laundering have on our economies”.

But it urged tougher rules to make public who owns companies and where they are based — a stipulation that has stirred discomfort in China, where the issue of communist leaders’ personal wealth is a political live wire.

The G20 countries, which represent 85 per cent of global economic output, committed to structural reforms that would lift their combined economic growth by at least 2.1 per cent by 2018.

That amounts to more than two trillion dollars, although economists are sceptical that many of the G20 members have the stomach for such reforms when growth is already slipping in some key countries, including China and Germany.

International Monetary Fund chief Christine Lagarde welcomed Sunday’s pledge while stressing: “Implementation is now critical, with a strong accountability framework to monitor progress, supported by the IMF.”

Oxfam said the focus on growth should be allied with a focus on reducing yawning levels of inequality around the world, “to ensure the bottom 40 per cent benefit more than the top 10 per cent”.

The G20 declaration also endorsed “strong and effective action” on climate change despite attempts to prevent its mention by Abbott, who wanted the focus to remain on the economy.

One European diplomat likened the G20 negotiations with Abbott to “trench warfare”, but the pro-climate lobby was confident of victory after Obama breathed new life into global discussions on greenhouse emissions with a surprise pact with China last week.

Real warfare remains the fear in Ukraine, where the West alleges that Russia is aiding and abetting rebels in the former Soviet satellite’s east.

In Brisbane, Obama and British Prime Minister David Cameron hammered home the West’s determination to curb Russian meddling in Ukraine, which the US president said violated international principles.

“One of those principles is that you don’t invade other countries or finance proxies and support them in ways that break up a country that has mechanisms for democratic elections,” he said.

Cameron said the West would maintain its campaign of sanctions for years if need be, because the alternative was allowing the Ukraine crisis to develop into “some permanent frozen conflict on the continent of Europe”.

German Chancellor Angela Merkel, who held lengthy talks with Putin far into the night in Brisbane, said after the G20 that it was “important to take advantage of every opportunity to talk”.

But she stressed: “There is a close agreement among Europeans about Ukraine and Russia.”