A pregnant woman in Victoria has tested positive for the Zika virus, Health Minister Jill Hennessy says.

Key points: Not yet known if baby of pregnant Victorian woman diagnosed with Zika is affected

Not yet known if baby of pregnant Victorian woman diagnosed with Zika is affected Officials say no risk to others as virus is not transmitted person to person

Officials say no risk to others as virus is not transmitted person to person Health alert issued for people travelling to countries where Zika is prevalent

Ms Hennessy said there was no risk to the public as the Zika virus is not transmitted person to person and was not present in Australian mosquitoes.

The woman was diagnosed this week after recently returning from a country where the virus was prevalent.

The virus was picked up in a blood test after the woman reported symptoms of an infection, including a rash and a fever.

"My primary concern today is not about a public health risk but a woman who is dealing with the anxiety of receiving news that is incredibly concerning," Ms Hennessy said.

"That's why the Department is doing absolutely everything they can to ensure that this woman receives all of the support and the care that she needs during this extremely difficult period."

The Zika virus is a mosquito-borne illness that has surged through Latin America and been linked to birth defects in children in the region.

Victoria's Chief Health Officer Dr Roscoe Taylor said it was not yet known if the woman's baby would be affected.

"We don't know what that possibility looks like. Over time there are ways of monitoring the progress of the foetus through ultrasound scans repeated over the course of the pregnancy, that will give guidance to the clinicians on whether there are any likely impacts," he said.

There is currently no cure or vaccine for the virus which, in most people, causes mild symptoms.

Three cases of the mosquito-borne virus have already been identified in Queensland this year, including one in a pregnant woman.

Australian Federal Police officers deployed overseas have also contracted the virus, but there have been no recorded cases among them in 2016.

People urged to get 'good quality information' before travel

Victoria's Health Department has released a health alert urging Victorians to "get access to good quality information" before travelling to countries where there was a Zika prevalence.

"We are advising all people, but especially pregnant women, or women who may be in trying or intending to get pregnant, to avoid travelling to those countries and places where there has been Zika outbreaks," Ms Hennessy said.

Dr Taylor said the virus had been identified in 25 countries, saying there had been active Zika virus transmission in Brazil and other parts of Central and South America.

He likened the virus to other mosquito-born tropical illnesses.

"The virus, normally can cause either no symptoms in about 80 per cent of cases or a mild illness that resolves usually after a few days," he said.

"The illness may include a fever, a rash which is sometimes itchy, and joint pains. Zika virus infection is actually similar to the other tropical infections dengue which is also transmitted by mosquitoes."