Premier Gladys Berejiklian says she is "appalled" that NSW Labor leader Michael Daley has thrown his support behind students skipping school on Friday for a national climate change rally.

In a strong endorsement of the strike, Mr Daley said young people had a "democratic right" to protest, describing it as a "demonstration of young leadership" and an opportunity to "realise their own personal power".

Premier Gladys Berejiklian and Deputy Premier John Barilaro, on Boyd Baling farm in Lismore. Credit:Janie Barrett

But Ms Berejiklian slammed Mr Daley's position, warning it was inappropriate for someone wanting to be premier to encourage children to miss school for any reason.

"Children are there to go to school and I absolutely support their rights to have views about the world and I absolutely support them expressing themselves but not during school," she said.