The analysis lends support to the views of NSW Labor leader Luke Foley and others that the new council was set up as a "rich super-council that the Liberals can never lose", but the government says it was just one of many mergers created under its forced amalgamations policy.

Election analyst Ben Raue from the Tally Room blog crunched the numbers on the new Parramatta boundaries based on voting patterns in local, state and federal elections since 2012, and found the new Parramatta was far more likely to be held by Liberals than the old.

"The shift north took out more Labor-friendly areas in Granville and added in more Liberal-friendly areas around the M2," he said.

Based on voting patterns from the last federal election, the Liberal two party-preferred vote in the old Parramatta was 50.3 per cent; after the changes it grew to 54 per cent, Mr Raue said.

Based on voting patterns in the state elections of 2015, the Liberal first preference vote went from 48.7 per cent to 52.1 per cent in the new Parramatta.

Based on the local elections of 2012, on the new boundaries the Liberal vote jumps from 36 per cent to 43.3 per cent.

"It's a classic gerrymander," said Greens MP David Shoebridge.

"The outcome is pretty ugly, delivering concentrated privilege to the north of Parramatta Road with less wealthy residents in the new Cumberland council to the south being abandoned.

"When you piece it together, you see deliberate Coalition gerrymander delivering just enough extra Coalition voters to control the expanded and cashed-up Parramatta council."

It comes as Parramatta City and its neighbouring Cumberland council, formed a year ago from the merger of Auburn and Holroyd, are locked in a bitter dispute over how to carve up cash reserves, assets and liabilities to fit with the new boundaries, as revealed in documents unearthed by a freedom of information campaign by the Greens.

"Cumberland Council is entitled to a $24.6 million cash transfer. This claim is based on allocation of total cash ... by the net resident, which we believe is the fairest and most equitable method," acting general manager Maxine Kenyon said.

Parramatta disputes the amount and argues for a different allocation method which would settle the claim for much less.

Parramatta administrator Amanda Chadwick declined to comment beyond confirming the councils were in the process of determining an arbitration forum.

In drawing up the new Parramatta council boundaries, the government ignored the recommendation of the Independent Local Government Review Panel that Auburn, Holroyd, Parramatta, parts of Hornsby and the Hills south of the M2 and the western third of Ryde should form a new mega-council.

The government also ignored IPART's tick of approval on financial grounds for a proposed merger of Auburn with Burwood and Canada Bay to form a Sydney Olympic Park Council.

Instead, Auburn was merged with Holroyd, missing out on a central business district, and gaining the traditionally Labor voting suburbs of Granville and Guildford in the old Parramatta council area.

Meanwhile Parramatta gained blue-ribbon Liberal areas of the Hills and Hornsby Shires, plus the high-rate paying commercial and residential suburbs in the north of the former Auburn council.

"It is suspicious," said Mr Raue, likening it to the way past Liberal governments hived off Labor-voting suburbs in the City of Sydney to form South Sydney councils.

"Whether or not it was intentional, the fact remains that the government created this situation where the council with the second-most important CBD in the city will be tilted in favour of the Liberals," he said.

Local Government Minister Gabrielle Upton said: "The decision to create new councils followed four years of extensive research and consultation. An independent delegate and the Boundaries Commission both considered and supported the City of Parramatta Council's merger proposal."

David Borger from the Western Sydney Business Chamber said in late 2015 that forcing the neighbouring Auburn and Holroyd councils together was nonsensical and would create "poverty stricken suburbs" in a council with a low rate base, no commerce or industry and no central district.

Mr Foley said when the merger was announced: "I think the greatest bit of boundary rigging is in Parramatta. A series of additions and subtractions to set up a great big rich super council in Parramatta that the Liberals can never lose."