The Government has revealed it will invest $305 million into the upgrade and repair of essential infrastructure at Auckland District Health Board.

Prime Minister Jacinda Ardern said it was "no secret" that hospitals had been underfunded for many years.

"That's left us a legacy of deferred maintenance and ageing infrastructure that we can no longer ignore."

In the 2018 Budget $750 million of new funding was set aside for capital projects.

"Today I'm announcing that $275 million of that will be spent at Auckland City Hospital, Starship Hospital and the Greenlane Clinical Centre," Ardern said.

"Auckland DHB will invest a further $30 million over the next three years."

It was a huge investment that would ensure the DHB could continue to deliver safe, quality care to its 500,000 patients, Ardern said.

The programme of work would include lift upgrades, new fire protection systems, new electrical substations and water storage.

The project would also improve energy efficiency and help reduce operating costs.

Health Minister Dr David Clark said this was much-needed work on the often invisible infrastructure that keeps the DHB's major hospitals running.

"While patients, whanau and staff may not immediately see a lot of difference as a result of this remediation programme, it will mean fewer operational failures, greater efficiency and responsiveness, and improved safety and resilience.

"This work will provide a foundation for the DHB to plan for the future healthcare needs of its communities.

"It is a necessary precursor for any future development of the Auckland City Hospital and Greenlane Clinical Centre sites."

Today's announcement was important for the people of Auckland, he said.

But there's no question that further investment would be needed to deal with a "backlog of building issues nationwide" and a growing population.

"This is a Government that is committed to our public health service and is prepared to invest in its future so that it is there when people need it."