The NSW government has allocated almost $100 million in next week's budget to kick-start the refurbishment of Sydney's Westmead Hospital.

The redevelopment of Sydney's Westmead Hospital will make the precinct a "healthcare city", NSW Premier Mike Baird says.

Almost $100 million has been allocated in Tuesday's budget for the first stage of hospital renovations, which will cost $900 million over four years.

The premier, speaking to reporters in Westmead on Wednesday, said the funding would fulfil his election promise.

"What we're creating here ... is the best healthcare city in the country and one of the best in the world," Mr Baird said.

"It's a kick-start to get this precinct going and it's a green light."

Of the $100 million allocated in 2016-17, more than $60 million will go towards a new acute services building with operating theatres and emergency departments for both adults and children.

Another $38 million will go towards a car park with up to 2000 spaces opening next year.

The number of healthcare workers employed at the precinct will grow from 12,000 to more than 25,000 after redevelopment, with 1000 construction workers to be employed on site.

Mr Baird hoped the facilities would provide a home for medicine's best and brightest.

"There's nothing better than handing over your loved ones to the best minds in the country and in many respects, the world," he said.

The total $900 million funding will encompass the acute services building, renovations to intensive care unit facilities and additional funding for Westmead Children's Hospital.

It will also include further funding for car parking.

NSW Health Minister Jillian Skinner said the measures would help health workers accommodate the changing needs of patients.

"It's really a dream come true for all of those who have been working here," Ms Skinner said.

"Westmead Hospital is an iconic but ageing hospital which has not had a major upgrade since the 1970s."