Buoyed by the legal triumph of Ku-ring-gai council against the NSW government's forced merger policy, Randwick council has made a belated decision to join the anti-merger fight.

Lawyers formally briefed Randwick City Council on its legal options last week, as it prepares to file a legal challenge against its forced merger with Woollahra and Waverley councils.

This follows a closed extraordinary council meeting on May 9, in which the council voted to pursue legal action after Labor councillors Tony Bowen and Kathy Neilson sought urgent advice from Ian Davidson, SC over the council's renewed prospects for appeal.

At the time the councillors commissioned the advice, which they funded themselves, Woollahra council's High Court application had not been granted, meaning Randwick council faced imminent dissolution should it be rejected.