Seventy-six cases of the Zika virus have now been diagnosed in Queensland.

Travellers from countries including Fiji, Tonga and Mexico have brought the virus to Australia, authorities say.

There have not been any recorded cases of the virus spreading between people inside Australia, but as the wet season approaches (when mosquito numbers boom after breeding), conditions could soon be ripe for an outbreak.

“This time of year from November onwards is rainy season. The temperature goes up so we have more mosquitoes,” said Dr Richard Gair, the director of the Tropical Public Health Services in Cairns.

“The efficiency with which mosquito can transmit the virus is increased.

“We've never seen a Zika outbreak in Australia, but if we're going to see a Zika outbreak we would expect it to be seen at the same time and the same place.”

The virus is spread both by mosquitoes and through sexual transmission, and is known to cause microcephaly – a condition that causes babies to be born with a greatly reduced cranium size.

Health authorities are working proactively to kill off mosquitoes in popular tourist spots, testing blood samples (focusing on areas where pregnant women might visit, such as schools, childcare centres and antenatal care centres) and running education programs about preventing mosquito bites.

Trying to prevent bites in the first place is likely to be the most effective measure, because adults rarely show any signs of Zika after they are infected, and so only find out when it harms their child.

The Australia Paediatric Surveillance Unit at Sydney’s Westmead Children's Hospital is monitoring all new cases of microcephaly in children.

“Microcephaly, or small head, usually implies that there's a small brain so it's usually associated with neuro-developmental problems and can be caused by a whole range of things, such as congenital infection,” Professor Elizabeth Elliott said.

“We were asked to conduct this study by the Federal Department of Health because when we looked at the prevalence, or frequency of microcephaly, we found that we really have very poor data in Australia.

“What the Zika virus has done has been to prompt us all over the world to say what is the normal expected frequency of microcephaly and if we see a blip in cases could it be due to say, the Zika virus.”