Twenty thousand police community support officers will be patrolling the streets of England and Wales by 2008, Gordon Brown has pledged.
There are currently 3,800 CSOs operating in England and Wales
The chancellor said Home Secretary David Blunkett had demanded year on year rises because it was "essential for stronger and safer communities".
Total spending on law and order was set to rise by £2.2bn to £14.9bn by 2008 to fund the extra officers, he said.
Mr Brown made the announcement in his spending review to the Commons.
He told MPs: "There is a clear consensus amongst the people of this country that to modernise the way we tackle crime and the fear of crime we need on our streets not just policemen and women, but CSOs at the heart of each neighbourhood."
He said that, as well as patrolling the streets, CSOs could build links with local people and combat anti-social behaviour.
The chancellor likened "strengthening the effectiveness" of the police force with CSOs to the way classroom assistants and teachers, and doctors and nurse practitioners worked together.
The home secretary will announce the detail of the plan next week, he said, while Scotland and Northern Ireland will make their own announcements.
'Back on beat'
BBC correspondent Andrew Tighe said provision for extra CSOs was a relatively cheap way of getting the message across to voters that the government is taking crime seriously.
It was a way of "putting police of a sort back on the beat" without having to pay the full price of a "traditional warranted uniformed bobby."
"The government has been prepared to hand money over to the Home Office to give this impression that a Labour government facing an election is taking crime seriously, is doing something about it", he added.
There are currently about 3,800 CSOs operating in England and Wales.
Officers focus on low level crime, disorder and anti-social behaviour, with the aim of allowing detectives to concentrate on more serious crimes.
Unlike police officers, CSOs are not called away for tasks such as court appearances, public order policing or case management.
As a result they tend to have a consistent presence in the community.
They can also compliment the work of officers by releasing them from tasks that do not require the full range of policing skills.
These include guarding the scenes of serious crimes, safely escorting abnormal loads and stopping vehicles for safety inspections.