The NSW government will invest $750 million into the redevelopment of Royal Prince Alfred Hospital starting with expansion of emergency and imaging departments.

The NSW government is promising $750 million to redevelop Sydney's Royal Prince Alfred Hospital, including a bigger emergency department and better operating theatres.

NSW Health Minister Brad Hazzard labelled it a "game changer" for medical staff and patients.

"RPA is a shining jewel in our health crown, and it is about to get the biggest investment in its 137-year history," he said in a statement on Tuesday.

The first stage of the redevelopment will focus on the expansion of emergency and imaging departments and operating theatres, and integration of ambulatory care services.

The government will invest more than $8 billion in health infrastructure over the next four years and has already invested nearly $10 billion since 2011, Mr Hazzard said.

However, Labor's health spokesman, Walt Secord, said that the government still has a lot of work to do.

"RPA is almost 140 years old and it is crumbling with staff shortages, poor infrastructure and a lack of funding under the Berejiklian government," he said in a statement on Tuesday.

Labor will be making further health and hospital announcements in the coming days with the issue "shaping up to be a key election battleground", Mr Secord said.