Union leaders have warned that without co-ordinated action to tackle the global recession, it could easily turn into a "prolonged slump".
The TUC said there were "worrying signs" that the G20 leaders attending the conference in London on April 2 would not rise to the occasion.
It comes amid reports some Euro nations are against a big fiscal stimulus and the US is against global regulation.
"We need both," TUC general secretary Brendan Barber said. "Without a big co-ordinated fiscal stimulus this could be a deep and dangerous recession that may easily turn into a prolonged slump.
"But the Europeans, who want to ensure that we never again face meltdown of the world's financial system and say we need a tough global system of regulation, are also right.
"Governments should listen to their unions who all want to see a fiscal stimulus, action on tax havens and effective regulation, whichever side of the Atlantic or Pacific they come from.
"Unions are clear that we need not just a short-term stimulus, but action to make sure the world emerges as a fairer and greener place from the recession.
"It is not too late to tell world leaders that the stakes for this summit are incredibly high."
The TUC is helping to organise a Put People First march for jobs, justice and climate next Saturday, which involves more than 100 unions, development agencies, environmental and campaign groups.
