Victoria's Chief Health Officer Brett Sutton says it is a reasonable measure for workers in health settings to wear face masks.

"Where community transmission isn't negligible ... masks are a reasonable thing to wear where you can't physically distance. But we're working up some communication materials and I'll have more to say on that in coming days," he said on Tuesday.

Professor Sutton said the advice was in line with statements made by the Australian Health Protection Principal Committee.

Western Health has taken extra precautions, making all staff wear personal protective equipment whether or not they are on the front line.

Workers must wear a surgical mask, face shield or eye protections, a spokeswoman told AAP.

The measures have been in place since July 1 at its main facilities in COVID-19 hot spots, including Footscray and Joan Kirner Women's and Children's hospitals.

This was extended to Williamstown and Sunbury Day hospitals on Tuesday.

Since the end of June, visitors and outpatients must wear a supplied surgical mask too.

It comes after Northern Hospital confirmed on Monday that seven emergency department workers tested positive to the virus in five days.

The Rail, Bus and Tram Union has called for masks to be mandatory on Victoria's public transport.

Australian Associated Press