A high school in the New South Wales Blue Mountains, west of Sydney, will close today after a member of the school tested positive for coronavirus.

Staff and students at Katoomba high school have been directed to self-isolate while health authorities trace who may have had contact with the infected person.

Watch the video above

The school hasn’t said whether the patient was a student or staff member.

“A member of the school community has returned a positive test for COVID-19,” the school said on Facebook on Thursday night.

“In accordance with NSW Health advice staff and students at the school should self-isolate for the next few days while the contact tracing process is finalised.

“Staff and students will be contacted and advised if they can resume school as normal on Monday, 16 March 2020 or if a further quarantine period will be required.”

It comes as the state’s chief health officer warns they’re expecting as many as 1.5 million people to be infected with COVID-19 in New South Wales alone.

More on 7NEWS.com.au

“We’re anticipating 20 per cent of the population in the first wave to be affected,” Dr Kerry Chant told a NSW budget estimates hearing on Thursday.

Katoomba High School is the fourth NSW school to close over coronavirus fears.

Earlier this week, St Patrick’s Marist College and Willoughby Girls High School were closed after students tested positive to the virus.

Last week, Epping Boys High School was forced to close after a student there also contracted the virus.