Labour will be the public's "first line of defence" against the coalition government's spending cuts, the party's leader, Ed Miliband, will say.

Miliband – who will vow to be the public's "voice in tough times" – will seize on local government cuts forced by the tight funding settlement at the launch of Labour's local election campaign later on Thursday to claim the coalition's reductions would cost the average family with two children £182 this year.

"Labour launches our election campaign with a clear pledge to people across the country – we will be your voice in tough times," he will say.

"Cuts designed by David Cameron and Nick Clegg are coming direct from Downing Street to your street. Families in every part of the country will be hit by these unfair cuts.

"Areas with the greatest need are being asked to bear the greatest burden. The worst-off areas are being hit the hardest, while the average family will be hit much harder than people in David Cameron's constituency.

"Labour will be your community's first line of defence against the damage being done by a Conservative-led government and their Liberal Democrat allies."

In an interview conducted prior to the launch, the Labour leader also underlined his support for "people power" by those demonstrating their opposition to government policies in street marches and rallies as "the kind of politics we need in this country".

The Labour leader has been mocked by Cameron and other critics for making a speech at the anti-cuts protest in London, organised by the TUC last weekend – notably for claiming that the march, attended by more than 250,000 people, followed the tradition of suffragettes, the civil rights movement in the US, and the anti-apartheid movement.

Miliband told BBC Radio 4's Today programme he was not trying to suggest that the government cuts were comparable to apartheid, but was making a point about the importance of the people exerting power.

"The march on Saturday was about politics being practised by people making their voice heard in a peaceful way," he said.

"That tradition of politics not just being about what happens at Westminster, or in legislative chambers, but about people themselves making a difference is an important tradition ... If politics is just practised by elites, and is just about you and me and people in Westminster, then actually I think many people will be alienated from that process."

He added: "Take the U-turn the government made on forests. That was people saying: 'You've got to change,' and I think that is the kind of politics we need in this country.

Miliband will kick-start the election campaign with a speech and a question and answer session in the Midlands.

Labour is claiming its councils charge less, on average, than Tory and Liberal Democrats authorities, to the tune of £207 and £40 respectively