There is no evidence students at NSW schools have infected staff with COVID-19, according to a study cited by the federal government in its push to reopen schools.

The National Centre for Immunisation Research and Surveillance probe looked at all 18 cases of COVID-19 found across 15 NSW schools between March and mid-April.

Researchers tracked the nine teachers and nine students confirmed as COVID-19 cases along with their 863 close contacts – some 735 students and 128 school staff members.

They found only two additional cases of COVID-19 – one primary school student and one high school student, neither of whom had passed on the virus to other people.

The researchers found no cases in which students infected staff with the coronavirus.

NCIRS Professor Professor Kristine Mccartney on Sunday told reporters the findings showed there was a low rate of COVID-19 transmission within schools and between children.

“I hope it provides strong reassurance of the safety of a return to school,” Prof Macartney said.

“At the beginning of the pandemic, it has been quite surprising.

“Our report really fits well with evidence from other countries – China, the very first report, from the WHO, Iceland, the Netherlands, all consistently showing children have very low rates of infection and get mild disease … it’s behaving very differently to other viruses.”

Pressure on the states

The federal government is increasing pressure on the states to return schools to normal as soon as possible, while jurisdictions continue to take a range of approaches.

NSW will from May 11 reintroduce face-to-face teaching for students on one day per week, ramping up to full attendance by the start of term three in late July.

Schools boss Mark Scott vows social distancing will remain in effect. Photo: AAP

NSW Department of Education secretary Mark Scott on Sunday said social distancing behaviour would still be required between teachers and parents.

He said a staggered approach to the resumption of schooling would remain necessary in order to help parents build confidence about their children’s safety on campus.

“What we’re saying particularly to our school principals and leadership teams is, think about how your staff are deployed, how your staffrooms operate, how you hold meetings … think carefully about how socially distancing best applies,” Mr Scott told reporters.

“We do want to provide that reassurance there will be space in schools and ensure there are not crowds congregating at the school gate, not having parents at the school.”

NSW chief health officer Dr Kerry Chant said that as of Sunday, 52 cases of COVID-19 had been confirmed in NSW in those aged between five and 17, with three minors hospitalised.

-AAP