Prime Minister Jacinda Ardern has unveiled a bumper $400 million infrastructure spending plan which she says will benefit almost every school in New Zealand.

The overall funding package, which is the largest spend on school infrastructure in 25 years, works out to be roughly $700 per student and will benefit more than 2000 schools across the country.

"Nearly every school and community in New Zealand will benefit from this windfall investment. I'm proud that students and teachers will be the first to benefit from our infrastructure upgrade," Ardern said.

Find out how much money each school is getting here

The sizable spending package comes after Finance Minister Grant Robertson yesterday announced the Government's plans to borrow more money to spend on infrastructure upgrades.

Speaking to media yesterday, he would not say what the money would be spent on.

But in her keynote speech at the Labour Party conference in Whanganui this weekend, Ardern said the schools investment was the first announcement in the Government's infrastructure package.

The amount of money a school will receive varies.

For example, Avondale Collage, Auckland Grammar and Hamilton Boys' High, which all have a roll of more than 2000 students, will receive $400,000 from the Government.

But smaller schools, like Kokopu and Paparoa Range which have rolls closer to 100 students, will get $50,000.

The funding is only available to schools opened before 2015.

The money is for "much-needed" infrastructure upgrades, including fixing classrooms and making them more modern, replacing roofing and guttering and resurfacing paved areas.

Ardern said the spending package was a "real shot in the arm" for schools across the country.

"I've visited plenty of schools and I'd be hard-pressed to name one that didn't have need. You hear horror stories about kids learning in damp, mouldy classrooms."

She also said the spend would be great for local tradespeople – "this is an opportunity for work at a local level in every town and city in the country."

Education Minister Chris Hipkins said the funding was a well-deserved early Christmas present for schools across New Zealand.

The money allocated to the schools must be spent within the next two years and special schools will receive $200,000 each, regardless of their roll size.

According to Government figures, roughly 70 per cent of New Zealand schools have an average building age of over more than 40 years.

For most of the schools, the extra funding represents a 40 per cent average increase over the next five years.

Meanwhile, Prime Minister Jacinda Ardern also used her keynote speech to announce the Government will extend the living wage to all non-teaching staff in schools, including cleaners, caretakers and grounds people.