The Northern Beaches Indoor Sports Centre (NBISC) at Warriewood has completed a $3.2million upgrade making it the largest indoor sports facility in Sydney's north.

The upgraded facility will officially open on Friday 30 September and offers an increase from four to six indoor multi-purpose courts, a new mezzanine level, and improved exterior landscaping.

"NBISC is used by over 5500 people each week for sports including basketball, netball, volleyball, wheelchair basketball, gymnastics," said Northern Beaches Council General Manager, Mark Ferguson.

Northern Beaches Council contributed cash and other services in kind towards this project with further funding from local groups and sporting associations, donations, grants, and borrowings from the Bendigo Bank.

"Council is delighted to have been a major contributor in the development and recent upgrades of this important community facility," Mr Ferguson said.

NBISC is a not for profit organisation set up to provide a first class indoor sports centre for use by the community.

The Hon Rob Stokes will officially open the Centre, and will be joined by members of The Sapphires Premier League netball team, and members from the Under 14 Girl's State Championship team.