THE leaders of the world's 20 largest economies have revealed a plan to boost global GDP by more than £1.2 trillion over five years by investing in infrastructure and increasing trade.

Australia's Prime Minister Tony Abbott said countries will hold each other to account by monitoring implementation of their commitments to boost growth.

The G20 wants to lift global GDP by 2 per cent above expected levels by 2018. The communique from the summit of G20 wealthy and emerging economies also revealed leaders plan to jump-start growth in part by creating a global infrastructure hub to help match potential investors with projects.

They also aim to reduce the gap between male and female participation in the workforce by 25 per cent by 2025.

The International Monetary Fund and Organisation for Economic Co-operation and Development will also play a role in monitoring progress and estimating the economic benefits. Speaking at the end of the summit in Brisbane, Mr Abbott said countries have agreed more than 800 measures to spur the global economy, which the International Monetary Fund says is facing a "new mediocre".

Australia's Prime Minister said: "The G20 has delivered real, practical outcomes and, because of the efforts that the G20 has made this year, culminating in the last 48 hours, people right around the world are going to be better off."

But with international agencies downgrading their global growth forecasts in recent months, the G20 - which represents around 85 per cent of the global economy - faces an uphill struggle to implement its plan. Growth in China and Japan has weakened and Europe is teetering on the brink of a recession.

Mr Abbott said leaders unanimously agreed expanding global trade would directly benefit countries and people around the world.

He added: "Trade is a key driver of growth, perhaps the key driver of growth, and we're focused on domestic reforms to facilitate trade as well as the importance of a strong global trading system."

Russian President Vladimir Putin left the summit early as US President Barack Obama accused Russia of invading Ukraine and Britain warned of a possible "frozen conflict" in Europe.

David Cameron said: "I think President Putin can see he is at a crossroads. If he continues to destabilise Ukraine there will be further sanctions, further measures. There is a cost to sanctions, but there would be a far greater cost in allowing a frozen conflict."