The request comes as the state experienced a sharp uptick in COVID-19 infections, with 2738 cases and four deaths reported on Tuesday.

It's a new single-day record for Victoria, well above the previous record of 2297 reported on October 14 this year.

After a drop on Monday, the number of active cases has risen again to 17,821.

There are 368 people in hospital, down on the seven-day average of 373, including 80 in intensive care and 33 on ventilators.

Testing sites are coming under intense pressure, particularly first thing in the morning when many have reached capacity before they've even opened for the day.

The health department says the request for travellers to get tested in the afternoon will reduce demand and get those with symptoms and close contacts through sites earlier.

They're also working with pathology provider 4Cyte, which is struggling to keep up with testing demand, exacerbated by a broken analyser.

Acting premier Jacinta Allan said the department was working with the company to find ways to make their system more efficient.

Tuesday's rise in case numbers came as it was revealed Victorian's health department fought to protect contact tracing data from being shared with third parties.

Worksafe Victoria sought contract tracing and hotel quarantine details from the state's health department during an investigation into Victoria's second wave outbreak last year.

But in closed Victorian Supreme Court hearings, protected by suppression orders, the request was challenged by the department.

Testing commander Jeroen Weimar said to his knowledge no information had ever been divulged, something later confirmed by the department.

"I believe if the community were aware of the Authority's attempts to obtain contact tracing information from the department for purposes other than contract tracing, there would be concern within the community about the security of their information and therefore a high risk that some cases may not be candid with contract tracers," Mr Weimar wrote in a sworn affidavit in June.

"If that were to occur it could have a devastating impact on the state's ability to control this outbreak and any future outbreak, and put hundreds of lives at risk."

WorkSafe charged the health department in September with 58 breaches of occupational health and safety legislation over alleged hotel quarantine failures that have been blamed for the state's second wave outbreak in 2020.

Ms Allan labelled some media reports on the data case "scaremongering".

"The Department of Health took this court action to do precisely what the Victorian government has said repeatedly and that is to protect Victorians' data, to protect this information," she said.

She said pandemic legislation post-dated a court ruling on the matter and includes stronger measures to protect information.

Opposition leader Matthew Guy said the data should remain secret.

"We were told it wouldn't be accessed for anything other than private health. It should not be used for anything else," he said on Tuesday.

Australian Associated Press