NSW Health Minister Brad Hazzard said school closures over virus fears are the "new norm" after he confirmed a new case of the coronavirus in Sydney.

He said the woman, in her 30s, had travelled recently from the Philippines.

Another case has just been confirmed in WA.

Of the new confirmed cases in NSW today Mr Hazzard said, “There was a 14-year-old boy and a 15-year-old-girl, both at year 10 at St Patrick’s Marist College, Dundas. There was also a 12-year-old, a young lady from Willoughby Girls High School.

“In regard to the two young people from Dundas, St Patrick’s Marist College, their fathers, aged in their 50s, have also been confirmed as having the coronavirus.

"We have the year seven student, her mum has also been confirmed as having COVID-19. She’s a lady of Iranian origin, but hasn’t travelled recently. So there’s a lot of work to do there to determine the source of that particular infection.”

He said the response from the schools has been very positive and that school closures are "likely to be the new norm" as authorities try to stop the spread of the virus.

“We’ve established now a clear orthodoxy, that is if a child or a staff member, or any other person within that school, is found to have the COVID-19 virus, then effectively a breather will be taken and a day out will be the immediate requirement,” he said.

“So tomorrow, both of the schools involved will take a day out, while health has time to do the work that health does so well, in terms of tracing contacts.”

The new case takes the number of cases in NSW to 47. There are 476 cases under investigation.

In WA, health minister Roger Cook says the state has confirmed its sixth case, in addition to the case reported this morning.

"The sixth case is the son of the woman who travelled from Jakarta and then on to Melbourne," he said.

"We’ve tested all her family and only her son has now shown up with the coronavirus.

"We are now working with that family to understand all their movements."