The spectre of a nasty electoral backlash over the NSW Baird government’s plans for council mergers is gaining momentum after voters in the safe blue ribbon seat of North Sydney delivered a stinging 13 per cent swing against Liberal candidate Trent Zimmerman in the Federal by-election on the weekend.

The double digit swing against the man anointed to replace former Treasurer Joe Hockey in NSW Liberals heartland is sure to reverberate through Macquarie Street as the state Liberals and the opposition attempt to extrapolate how the swing could hit their own votes at the next poll.

North Sydney might be a federal seat, but state number crunchers have already started examining the entrails of the by-election result to calculate potential exposure.

As NSW state elections are legislatively mandated to be held in New South Wales on the last Saturday in March every 4 years, the Baird government is certain to have one eye to any early warnings that the forced merger process could turn deeply toxic and materially derail campaigning efforts in the lead-up to 2019 poll.

A victorious Mr Zimmerman on Sunday himself sheeted part of the blame home for the 13 per cent swing back to the amalgamation battle

“On amalgamations, I suspect there was some impact,” Mr Zimmerman was quoted telling Fairfax Media.

The fact that a victorious federal candidate in a government riding high in the polls is even talking about local government issues immediately after a result is certain raise eyebrows across all jurisdictions.

So far the Baird government has indicated it will make a decision on which NSW councils will be amalgamated – voluntarily or otherwise – by the end of this year, a timetable sure to be exploited by anti-amalgamation groups that include as members many Liberal-leaning councils.

But Liberal insiders on Monday were privately hosing down suggestions that the size of the North Sydney swing was propelled by hostility to council mergers, instead putting it down to a mixture of the pre-selection process and strong campaigning by independents in the Federal seat.

One view is that loyal Coalition voters were deeply unimpressed by the internal contestability for what is a largely an unassailable seat and chose to register their displeasure at the appointment of someone who was essentially a creation of the party political factional system – knowing full well that Mr Zimmerman would still win.

The utility of pushing a protest vote on what is essentially a local and state government issue in a Federal poll was also questioned by a Liberal source on the basis that it would have little or no material effect outside of the internal politics of the Liberal itself.

But the antennae are up.

One of those who has been helping Mr Zimmerman on the hustings is the Turnbull government’s new Local Government minister, Paul Fletcher whose electorate of Bradfield neighbours the seat of North Sydney.

Sydney’s leafy and affluent North Shore has long been a hotbed of resistance to council mergers and urban redevelopment with Mr Baird’s predecessor Barry O’Farrell using the restoration of council powers to check rapid urban infill growth on transport corridors as a key tactic to help oust Labor in the 2011 state election.

A major difference of opinion within parts of the Coalition is whether the pursuit of bigger councils actively goes against the core philosophy of ‘small government’ by creating larger bureaucratic entities that are inherently less flexible and responsive to community needs and concerns.

Another worry is that the amalgamation process could entrench the power base of some ambitious councillors and managers who appeared more motivated by “corporatised empire building” than dealing with grass roots issues.

Feeding into that suspicion is a clearly a reinvigorated interest from Canberra in the local government sector as a fast delivery vehicle for federally funded initiatives and projects that provide more immediate and visible impact than the convoluted Council of Australian Governments (COAG) process where money first has to filter through the states.

Meanwhile, experts are already looking at how much political capital will need to be spent to make NSW council mergers happen.

In November Dr Bligh Grant, Senior Lecturer at UTS’ Australian Centre for Excellence in Local Government (ACELG), told Government News there could be a high price for boldness.

“The political backlash will be felt at the state level: If councils amalgamate – even if they don’t – I think it’s reasonable to expect some political backlash against both the Liberals AND the Nationals in the next State election,” Dr Grant said at the time.

“Certainly there are political risks for the state government in this process. For example, following the forced amalgamations of local government in Queensland in 2008 the swing against the incumbent Bligh Labor Government in the state election in 2012 was 15.7 per cent – the largest swing in Australia’s political history.