The Crown Prosecution Service will receive an extra £85m over the next two years, to help deal with a rise in violent crime.
It comes as Boris Johnson launches a review of sentencing of the most dangerous and prolific offenders.
He said dangerous criminals must be taken off the streets and punishments “fit the crime” if the public was to have confidence in the justice system.
The news fuels speculation ministers are preparing for an early election.
On Sunday the prime minister promised to create an extra 10,000 new prison places and expand stop-and-search powers.
And on Monday Mr Johnson will host a round-table meeting in Downing Street with leaders from the police, probation and prison sectors.
Ahead of the meeting Mr Johnson said: “We have all seen examples of rapists and murderers let out too soon or people offending again as soon as they’re released.
“This ends now. We want them caught, locked up, punished and properly rehabilitated.”
The review, which will begin immediately, will look at whether violent and sexual offenders are serving sentences that reflect the severity of their crimes.
It will report back in the autumn.
More jail time
Under the current system, criminals sentenced to 12 months or more serve the first half of their time in prison and the second half “on licence” in the community, where they may be subject to recall.
The review will consider whether the law needs to be changed so offenders spend more time in jail.
The government’s focus on law and order will add to speculation that No 10 is preparing for an autumn general election, said BBC political correspondent Jonathan Blake.
Downing Street said the extra £85m for the CPS – which prosecutes criminal cases in England and Wales – will help staff respond to the rise in violent crime and an “explosion of digital evidence”.
Director of public prosecutions Max Hill QC said the money came at a “crucial time” for criminal justice.
In 2018-19 the CPS received £528m in government funding, according to its annual report.
The extra £85m will be paid for by the Treasury, a No 10 spokeswoman told the BBC.
Mr Hill said: “Our work is changing, and this new funding will provide the increased capacity to enable us to respond effectively to challenging trends we currently face.”
A spokesman from the CPS said the money would also help deal with the higher caseload they were anticipating as a result of Mr Johnson’s plan to recruit 20,000 more police officers.
Opposition parties warned there was no easy fix for the current rise in violent crime.
Liberal Democrat justice spokeswoman Wera Hobhouse said increasing prison sentences would merely “overcrowd prisons and waste millions of pounds”.
She said: “For years, Labour and Tory ministers have made sentences longer and longer, without any evidence that they prevent crime.
“It may sound tough, but it hasn’t made our communities any safer.”
And Labour’s shadow home secretary, Diane Abbott, said increasing the number of stop-and-searches was a “recipe for unrest”.