Prime Minister Jacinda Ardern has announced a "Future of Work Forum" which brings together unions, government, and business.

The forum's work is expected to build on work Labour did in opposition in reaction to increased automation and fluidity of jobs.

Ardern announced the forum at a pre-Budget address to a Business NZ lunch.

"This Government is keen to future-proof our economy, to have both budget sustainability and environmental sustainability, to prepare people for climate change and the fact that 40 per cent of today's jobs will not exist in a few decades," Ardern said.

READ MORE: Grant Robertson promises a surplus and defends budget responsibility rules

Finance Minister Grant Robertson will lead the work alongside Business NZ's Kirk Hope and Council of Trade Unions president Richard Wagstaff.

"This forum will help us shape the policies we will need so workers and businesses can be equipped to adapt to the rapidly changing nature of work.

The wider pre-Budget speech saw Ardern making clear her Government's commitment to their budget responsibility rules.

"We know we have to live within our means and we will," Ardern said.

"At the same time, we want to lift productivity, education, research and development, and address skill shortages. This will involve increases in both public investment as well as incentives for business.

"You will see a clear commitment to investing in the critical services we rely on and addressing areas of neglect. This Government will make targeted investments to address our social and infrastructure deficits."

This echoed remarks made by Grant Robertson at his pre-budget speech on Tuesday.

Robertson and Ardern promised surpluses across economic cycles unless there was a compelling reason - such as an earthquake or financial crisis - to spend more than expected.