How much Sydneysiders will pay under a new system to help fund NSW fire and emergency services can be revealed, with some property owners facing annual bills exceeding $500.

From July 1, NSW property owners will be charged the new Fire and Emergency Services Levy based on land value determined by the NSW Valuer-General, replacing the previous system which was a tax on insurance policies.

Fairfax Media can reveal an owner of residential property in the Mosman council area whose land is worth the local median land value of $1.84 million will pay $502.96 for the 2017-18 financial year.

However, in Fairfield, where the local government area's median land value is $461,000, the annual levy for the owner of such a property will be $200.96.