David Cameron has told fellow G8 leaders they must start work now on preparing "bold steps" to take when they meet in Northern Ireland in June for the annual summit.
The Prime Minister, in a letter marking the start of the UK's presidency of the group, warned he would not allow a summit where rich nations "simply whip out a chequebook at the 11th hour, pledge some money and call it a success".
And he signalled that the UK was looking for concrete moves in three key areas - including the potential for signing up to an anti-corruption measure for extraction industries to encourage poorer countries to follow suit. There could also be new measures to tackle global tax avoidance, he suggested.
The summit will see US president Barack Obama, Russian president Vladimir Putin, German chancellor Angela Merkel and other world leaders gather for two days at the Lough Erne golf resort in Co Fermanagh. It will be the first time the annual summit has been held in the UK since Gleneagles in Scotland in 2005 - the last occasion the British Government chaired the G8.
In his letter, Mr Cameron said the world continued to face "grave economic uncertainty" in 2013 and that the top priority would remain each country's own domestic challenges. But he added: "As leaders of eight countries making up around half of the world's entire GDP, the ambitious standards we set and the bold steps we take by working together through the G8 can make a tangible difference by firing up economies and driving prosperity, not just in our own countries, but all over the world.
"I hope that at Lough Erne we can seize this opportunity. At the heart of my agenda for the summit are three issues - advancing trade, ensuring tax compliance and promoting greater transparency.
"All of them are areas where I believe the G8 can play a distinctive role, using our commitment to open economies, open governments and open societies to support enterprise and deliver economic growth. But to achieve this will require strong political leadership and months of detailed policy work from our teams.
"This G8 will not be the kind of summit where we simply whip out a chequebook at the 11th hour, pledge some money and call it a success. What we are talking about are long-term changes in our countries and the rules that govern the relationships between them. With ambition on this scale, I am convinced that success depends on us starting a debate on these changes now."
Shadow Treasury minister Catherine McKinnell said: "Promoting growth and jobs, alongside tackling tax avoidance, must be at the top of the G8's agenda this year. But David Cameron cannot offer the leadership and change we need while he sticks to his failing economic policies at home.
"Over the last year David Cameron's policies have seen prices rise faster than wages, a flatlining economy, rising long-term unemployment and the deficit going up. And the price for this economic failure will be paid for by millions of working families who will see their tax credits cut while millionaires get their tax bill reduced this year. We urgently need a change of course, with policies that stimulate rather than stifle economic growth and ensure that prosperity is more fairly shared."