The world's largest economies will be represented in London
Union leaders from the UK and overseas have put forward a global five-point plan they want G20 leaders to adopt as a way of tackling the economic crisis.
The plan includes job creation, some bank nationalisation, tackling wage deflation, and climate change action.
The ITUC union body said global economic "neo-liberalism" had failed.
The G20 meeting in early April brings together leaders from industrial and emerging market countries that make up 85% of the world economy.
"If the G20 governments in London are only able to agree on half-measures, they will have failed to meet their responsibilities," said ITUC General Secretary Guy Ryder.
"As the world's largest economies, they have the responsibility and the possibility to replace the failed neo-liberalism of the past with a whole new direction for globalisation."
The Brussels-based body, which represents 170 million workers in 312 affiliated national organisations from 157 countries, wants to see:
- a co-ordinated international recovery and sustainable growth plan to create jobs and ensure public investment
- nationalisation of insolvent banks and new financial regulations
- action to combat the risk of wage deflation and reverse decades of increasing inequality
- increased action on climate change
- new international legal framework to regulate the global economy, and reform of the IMF, World Bank, OECD, WTO
But the UK-based union grouping the TUC said there were worrying signs that the G20 leaders attending the conference in London would not meet the challenges ahead.
G20 LONDON SUMMIT
World leaders will meet next month in London to discuss measures to tackle the downturn. See
our in-depth guide
to the G20 summit.
The G20 countries are Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey, the United Kingdom, the US and the EU.
It also expressed worry at reports some European politicians were resistant to a fiscal stimulus, and that some in the new US administration were opposed to more 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."
The weekend before the summit, the TUC is helping to organise a Put People First march involving more than 100 unions, development agencies, environmental and campaign groups.
'Anger out there'
However, alongside such peaceful actions, police fear a number of hard-line protesters will attempt to bring central London to a standstill with a series of demonstrations.
On Sunday Foreign Office Minister Lord Malloch-Brown told the BBC's Andrew Marr Show there was "enough anger out there" for people to support any major demonstrations around the G2 meeting.
But he appealed to potential protesters to not "disrupt a critical moment to try and get the global economy moving again".
Lord Malloch-Brown told BBC1's Andrew Marr Show that he hoped the majority of protesters would be demonstrating "on behalf of the summit" to highlight the needs of the "poor" and the "workers".
"That will overshadow probably a handful of real hardcore troublemakers," he said.