Deadline looms for NSW council mergers

About 20 Sydney councils have submitted preferences for mergers ahead of a controversial midnight amalgamation deadline.

By the end of Wednesday councils across NSW are expected to nominate whether they will amalgamate and with who, in a move estimated to free up $2 billion in rates over 20 years.

Local Government Minister Paul Toole said Leichhardt, Marrickville, Ashfield, Gosford and Wyong had already submitted preferences as well as Newcastle.

The government, he said, had offered "significant funding" to help with the costs of mergers, with the details of the process expected to be finalised by the end of the year.

At an anti-amalgamation rally, which drew hundreds earlier on Wednesday, state Greens MP David Shoebridge urged those against the plans to keep fighting.

Opponents say council amalgamations will be forced on those local governments who don't want to merge.

But Mr Toole said the government hadn't made a decision.

"We are looking at all options available but what we are very keen to do is work with councils," he said.

Holroyd Mayor Greg Cummins, a fierce critic, said under one proposal a mega-council in western Sydney would be responsible for 450,000 people.

"I fail to see how you will get any sort of fair-dinkum representation for your local community in a council that size," he said.