Monte Sant' Angelo Mercy College in Sydney's north has banned the sale of plastic water bottles.

The canteen will no longer stock plastic water bottles and the school also spent $7,500 installing water bubblers for the students to use instead.

The initiative will be launched today by sailor activist David de Rothschild who this week completed a voyage across the Pacific Ocean on the Plastiki, a boat made from recycled bottles.

Year 12 student Claudia Saunders says she hopes the ban will do more than reduce the school's consumption of plastic bottles.

"It's also about promoting it to Monte girls and getting the awareness out there how unnecessary these bottles are and the damage they can cause to the environment, both in their production and then in their disposal," she said.

The school's effort has been hailed as a model that can be rolled out across the country.

Jon Dee, founder of the environment group Do Something, says the campaign will significantly reduce the amount of plastic waste at the school.

"We'll have 1,100 girls at this school who won't have bottled water," he said.

"Now if they can do that at Monte Sant' Angelo there's no reason why other schools couldn't follow this example.

"It will set a great environmental role model for the kids but it will also show kids you can help the environment and you can save money at the same time."