A New Democratic Party government will expand child support up to $400 per child a month, Leader Jack Layton said Sunday.

"This benefit, modelled on the existing Canada Child Tax Benefit, will expand in phases to $5,000 a year per child, and consolidate the current piecemeal system of benefits and tax credits for children into a single, better, non-taxable monthly cheque to parents," Layton said.

The benefit will cost the government $4.4 billion by the fourth year of the new program, the single most expensive item in the NDP's spending plans.

Layton described the change as the centrepiece of the NDP platform, officially unveiled Sunday after two weeks of campaigning and a slew of promises.

He also said his party would create 220,000 new child-care spaces by the fourth year of its government.

The NDP will finance spending promises by rolling back cuts to corporate taxes. "We'll restore a uniform 22.12 per cent tax rate — what it was before the [Liberal Paul] Martin and [Conservative Stephen] Harper governments began these giveaways," according to the platform document.

That would give the government $40 billion more revenue over four years, which would be re-allocated to the NDP's spending priorities. The party would not run a deficit, the policy document states.

"We're making it clear with this platform today that our priorities are those of the kitchen table, not just the boardroom table," Layton said.

The party also expects to have a "peace dividend" of $600 million in the first  year and $2.2  billion in the following two years after cancelling Canada's mission in Afghanistan.

In terms of spending, the NDP has already promised a pharmacare program, more training for workers and $5 billion over five years for First Nations, Métis, and Inuit communities to improve health, housing, water and infrastructure.