Labour is promising to put 10,000 additional police on the streets of England and Wales if it gains power in the General Election on June 8.
In his latest campaign pledge, Labour leader Jeremy Corbyn said extra "bobbies on the beat" would be funded by reversing Conservative cuts to capital gains tax (CGT).
The party said going ahead with the cut to the higher rate of CGT from 28% to 20% and basic rate from 18% to 10% announced in last year's Budget would cost public services more than £2.7 billion over five years.
However, the Conservatives dismissed the proposal as "nonsensical", saying Labour had already committed the CGT savings to fund other pledges, although Labour insisted it was fully funded.
The move will be seen as an attempt by Mr Corbyn to claim the political initiative on law and order - an issue on which he has been accused of being weak in the past.
Labour said that under its plan, funding would be provided for the 43 forces in England and Wales to take on 10,000 additional officers in community policing roles - the equivalent of one officer for every electoral ward - at a cost of £300 million a year by 2021/22.
Speaking in Southampton on Tuesday, Mr Corbyn will attack what he will say have been "unacceptable" cuts to policing under the Tories, with a 20,000 fall in officer numbers since the Conservatives came to power in 2010.
"Cutting police numbers especially when there is more crime to deal with is unacceptable. The safety of our communities is vital to us all," he will say.
"Community policing means uniformed officers being visible, local and accessible. They engage with the public, have a detailed local knowledge and build a network of relationships."
Shadow home secretary Diane Abbott MP will say: "Theresa May failed to protect communities as home secretary and has continued to fail them as Prime Minister.
"Labour will reverse the Tories' tax breaks for the rich, providing new money that can be used to put a bobby on the beat in every electoral ward in the country."
But the Conservatives said Labour had already promised to spend the savings from CGT on schools, welfare and the arts.
Policing minister Brandon Lewis said: "This is just another nonsensical Jeremy Corbyn idea which he can't pay for because his sums don't add up and he's already spent the money for it three other ways.
"Jeremy Corbyn promises all sorts of things but we all know he can't deliver. He and his supporters want to take away the powers the police need to keep us safe."
"Under Theresa May, the police have cut traditionally-measured crime by a third, and with her strong and stable leadership we will be able to make communities even safer."
Liberal Democrat leader Tim Farron, meanwhile, will attack Labour for taking the votes of ethnic minority communities for granted.
At an event at Westminster Synagogue he will say the party was not even bothering to engage with some communities because it believed the ethnic minorities would vote Labour regardless.
But the Lib Dems have themselves come under fire from Theresa May who accused them of preparing to "prop up" Jeremy Corbyn in government so they could derail the Brexit process.
The Prime Minister is campaigning in the South West where the Tories are preparing to fend of a fightback from the Lib Dems who are hoping to regain seats they lost to the Conservatives in the 2015 general election.