Nick Clegg is expected to launch the Liberal Democrats' local election campaign by claiming the Conservatives waste taxpayers' money.
He will say that despite their stated differences, a vote for Labour or the Tories was the same thing, as both had a record of waste and inefficiency.
And the deputy prime minister will argue that his party spreads "the burden of austerity fairly".
Mr Clegg's speech will mark the start of campaigning for the 2 May poll.
He will tell voters in Cornwall: "Difficult decisions will need to be made in local government, just as in national government, and people understand that. But they - rightly - expect that their representatives should make the fairest possible decisions.
"Next month, in wards across the country, people will be confronted with the same choice. Despite all their stated differences, a vote for Labour or the Tories will be a vote for the same thing.
"Their record in local government shows that even when millions of families are feeling the pinch, they'll both squander taxpayers' money on waste, inefficiency and their own vanity projects.
"A vote for the Liberal Democrats, on the other hand, is a vote for a party which - wherever we're in power - does its best to spread the burden of austerity fairly, investing in jobs and help for hard-pressed families."
Ed Miliband is also set to launch Labour's campaign on Monday, with a speech in which he is expected to say local councils should be allowed to prevent shops opening, such as payday lenders and bookmakers.
He will say the policy pledge forms one of five key election messages his party will be campaigning on.