The NSW government has promised to deliver a fix for Hornsby council, which was left financially depleted and with reduced territory as a result of the government's backflip on its signature council merger policy.

The policy backflip scrapped any remaining hope the council had of securing the vaunted $70 million of benefits of merging with Ku-ring -gai after the NSW Court of Appeal ruled the merger invalid in March.

Hornsby MP Matt Kean said the government is considering a "range of options" to ensure Hornsby residents are not left financially worse off due to the council merger backflip. Credit:James Alcock

The council is now lobbying the government for the return of the territory it surrendered to the new City of Parramatta Council on the promise of the financial benefits of merging with Ku-ring-gai.

Financially modelling, released by Hornsby Council in June, indicated it would be left up to $200 million out of pocket over the next decade because of the boundary changes.