Gordon Brown is to host talks with business and union leaders about measures aimed at safeguarding jobs during the downturn.
With 1.8 million people out of work, the prime minister is expected to warn that a failure to act now will mean a deeper and longer recession.
Work and Pensions Secretary James Purnell will also give details on a plan to help the long-term unemployed.
The Tories have dismissed the meeting as an exercise in spin.
Mr Brown is expected to open the jobs summit at the Science Museum in London with a warning that a deeper recession would mean whole communities being written off and lasting damage to the economy.
Cash inducements
BBC political correspondent Carole Walker said the prime minister will pledge "this will not happen on my watch".
Before Christmas the number of people out of work stood at 1.8 million and some economists believe it could approach three million by 2010.
To combat that Mr Brown will set out plans to prepare Britain for growth in sectors such as environmental technology, advanced manufacturing, health care and education.
As part of the summit Mr Purnell will give details of a £500m scheme to help people who have been out of work for more than six months.
That could include paying employers up to £2,500 for every person they recruit and train, if they have been out of work for more than six months.
The government will hear from small business leaders - the Federation of Small Business has launched a five-point plan which it says could create up to 400,000 new jobs.
Measures it is calling for include the promotion of part-time working, simplified regulation and less taxes.
It also wants to see more investment in apprenticeships, and greater opportunity for small firms to bid for government contracts.
Union leaders at the summit will propose more training and job creation programmes, while environmental campaigners want greater investment in energy efficiency.
The Conservatives are dismissing the event as more spin than substance, designed they say to cover up the fact that Mr Brown's recession policies are not working.
