As many as 300,000 workers who are following Premier Gladys Berejiklian's plea to keep children home from school will be denied special coronavirus leave because schools remain open.

Ms Berejiklian and NSW Education Minister Sarah Mitchell have repeatedly urged parents not to send their children to school unless absolutely necessary.

Premier Gladys Berejiklian has repeatedly urged parents not to send their children to school if not necessary. Credit:AAP

But because schools remain technically open, NSW's 325,000-plus government workers cannot access 20 days of special COVID-19 leave if they choose to keep their children home from school.

About 89 per cent of children did not attend NSW public schools on Thursday, as the number of new coronavirus cases increased by 190, taking the total number in the state to 1219.