Ryde Labor councillor Jerome Laxale with NSW Opposition Leader Luke Foley and candidate Peter Kim on Sunday. Party figures privately admitted they had underperformed in some key councils such as Georges River, formed through the merger of Hurstville and Kogarah councils. It had previously enjoyed a majority on Kogarah council but secured only one-third of seats on the new council. Labor is on track to outperform the Liberals in four of the seven new Sydney councils, created through the mergers, while the Greens claimed to have increased their total councillors by up to one-third while cresting a voter backlash. In Canterbury-Bankstown – now the largest council in NSW with more than 350,000 residents – Labor has secured a controlling majority of eight of the 15 seats. "What we saw yesterday across NSW was the Liberals receive a hiding," triumphant Opposition Leader Luke Foley said. "They forced mergers, they rigged boundaries and people across NSW punished them."

Labor's new line of attack on the government was also employed successfully by the Greens in Liberal heartland, where the party suffered swings of up to 10 per cent in areas such as Waverley and Lane Cove. "NSW has seen through the ugly politics of forced amalgamations, privatisation and overdevelopment being pushed by the Liberal government and demanded change," Greens MP and local government spokesman David Shoebridge said. The Greens claimed to double its representation from four seats to eight across the three eastern suburbs councils – Randwick, Waverley and Woollahra councils – while running on its anti-development agenda. In Waverley, the Liberals have lost their majority on council, reduced from seven seats to five. The results will almost certainly end the three-year reign of Liberal mayor Sally Betts – a Liberal powerbroker in Sydney's eastern suburbs and part-time staffer to Prime Minister Malcolm Turnbull – who won't have the numbers to retain the mayoralty which will be decided by the incoming councillors.

Cr Betts steered the council through a turbulent 12 months, in which significant community backlash was levelled against the Liberals over local issues such as the Bondi Pavilion upgrade. Hornsby council – where former federal MP Philip Ruddock won a thumping victory in the mayoral race – is also set to have an interesting dynamic, after the Greens won two seats, ending an eight-year dry spell for the party in the blue-ribbon area. But the party's loss of a seat on the newly merged crown jewel of Sydney's west, Parramatta Council, could be viewed as especially significant by opponents who accused the government of a "historic gerrymander" to redraw its boundaries to its own advantage. The Liberals there, racked by recent infighting, have won six of the 15 seats, while Labor have retained five, and the remaining four are expected to be held by independents. On the new Inner West Council – formed from the merger of Marrickville, Leichhardt and Ashfield councils – the Liberal party's influence in the region has declined to just two seats. It previously held 10 of the 36 seats across the three councils.

The new council will be dominated by Labor and the Greens, which picked up five seats each. Independent candidates have won two seats, one of whom is prominent anti-WestConnex campaigner Pauline Lockie. Under NSW's system of preference allocation counting for the final results could take some days yet. In the Northern Beaches council – created through the merger of Manly, Pittwater and Warringah councils – four seats are yet to be decided, but the Liberals are expected to pick up at least five seats while independents have won six seats. Also hanging in the balance were the fortunes of former lobbyist and Liberal Zac Miles, whose mayoral race for Hunter's Hill appeared likely to be determined on preferences against two independents. Premier Gladys Berejiklian was muted in her response to the results on Sunday, saying only that she was "pleased with the outcome across the board because the community has had its say".