Two NSW councils have won an appeal to have their forced mergers set aside.

The State Government’s merger process has already created 20 new councils, reducing 152 councils to 112, sacking hundreds of councillors and leaving the areas in charge of unelected administrators.

The New South Wales Land and Environment Court has ruled on one appeal from Mosman and North Sydney councils against their proposed merger with Willoughby City Council, and a second appeal from Strathfield Council against its proposed merger with Burwood and Canada Bay councils.

Justice Timothy Moore said there was “no proper statutory foundation” for the planned amalgamations, due to flaws in reports by government-appointed delegates the recommended the mergers.

NSW Local Government Minister Paul Toole said he welcomed the judgment.

“The court actually found the delegate did not adequately consider two of the 11 factors outlined by the Local Government Act,” he said.

“It looks at things such as the geography, communities of interest, the finances representation.

“This is a matter that'll go back to the local delegate and it will actually be for their determination for review and further examination.”

Four other councils - Hunter's Hill, Lane Cove, Ku-ring-gai and Shellharbour - appealed against their proposed mergers too, only got Justice Moore to dismiss their cases.

The judge he said their complaints were unfounded.

Richard Quinn, the Mayor of Hunter's Hill, said it was a disappointing ruling, especially since an alleged 80 per cent of the community opposes the mergers.

Save Our Councils coalition president Carolyn Corrigan, a Mosman Council member, was questioned about the expense of fighting the amalgamations.

“Sure there's an expense, but the bigger expense is the loss of local democracy,” she said.

“It's an absolutely priceless right that we have.”

The four unsuccessful councils have a week to appeal against the outcome.