Voters in the national capital are off to the polls tomorrow to determine whether the nation’s longest-surviving government will be allowed to add yet more miles to its clock.

Labor took the reins in the Australian Capital Territory way back in 2001, has been re-elected three times since, and is now on to its third chief minister.

Twelve years of accumulated grievances was nearly enough to tip the scales at the last election in 2012, despite the image makeover Labor received the previous year when Katy Gallagher replaced Jon Stanhope after a decade in the top job.

Gallagher moved to federal politics in December 2014, bequeathing to her successor, Andrew Barr, a very low margin of error in his looming bid to secure Labor a fifth term.

But in a town where a third of the work force is employed by the public sector, there is no such thing as an easy win for the Liberals.

The last party leader who struck the appropriate note of ideological moderation and business-like efficiency was Kate Carnell, whose strong electoral performances in 1995 and 1998 sustained the Liberals in minority government from 1995 until the present government came to power in 2001.

Since that time, the Canberra Liberals have suffered from a tendency to list further to the right than the electoral good judgement demands.

Their leader at the last two elections was Zed Seselja, who has made a name for himself as a conservative Tony Abbott loyalist since moving to the Senate in 2013.

Labor has taken every opportunity to ensure that Seselja’s successor, Jeremy Hanson, has been tarred with the same brush — notably during Tuesday’s leaders debate, when Andrew Barr insisted on referring to him as “my conservative colleague”.

[Poll Bludger: Australian Capital Territory election guide]

Hanson insists that he’s a moderate, pleading liberal views on abortion, republicanism and same-sex marriage.

However, his parliamentary ranks include high-profile conservatives in Alistair Coe, who has risen swiftly to the deputy leadership, and Giulia Jones, a former staffer to Tony Abbott.

Labor’s efforts to emphasise the point were assisted when Gary Humphries, who had lost his Senate preselection to Seselja before the 2013 federal election, wrote in The Canberra Times of a “creeping conservatism” in the party that had left Labor as “the natural party of government in the ACT, comfortable in their skin and with an electorate comfortable with their take on progressive Labor-left, especially when a Coalition government perches on Capital Hill”.

The accuracy of Humphries’ insight will be tested tomorrow under re-upholstered electoral arrangements that will boost the Legislative Assembly from 17 members to 25 — the largest parliamentary upgrade that Australian politicians have been game to try on in three decades.

Where formerly the territory’s proportional representation regime was based around three electoral districts, of which two had five members and one had seven, there will now be five electorates with five members each detailed guide to the electorates can be found on my blog, The Poll Bludger).

This was the fruit of a deal struck between Labor and Liberal over the objections of the Greens, whose interests would be better served by more members per district.

Whichever party ends up forming government will have done so by securing the support of at least three members in at least three electorates.

The Liberals at least look likely to achieve this in Brindabella at the southern end of Canberra, which existed in slightly larger form under the old regime and returned three Liberals in 2012.

Their cause here has been boosted by the government’s contentious plan to build a light rail line through the northern suburbs, leaving the other end of town with only the distant promise of a future second stage.

The weakest of the five prospects for the Liberals is Kurrajong, which encompasses the parliamentary district and city centre, and is accordingly dominated by younger public servants with neither mortgages nor families.

It is here that Shane Rattenbury, the sole Greens survivor after the party’s poor performance in 2012, is planting his flag. Past form suggests he will retain his seat, with the other four Kurrajong seats to be divided between Labor and Liberal.

The wild cards are Yerrabi, Ginninderra and Murrumbidgee, which cover the city’s north and west.

Reports suggest Labor is pessimistic about scoring more than two seats per district, and is instead counting on the Greens to gain the seats required for a left-of-centre majority.

A large number of other minor players are also in the field, but they have a formidable 16.7% quota for election to amass, and the territory seems to have lost the enthusiasm for independents that characterised its politics in the years after self-government was introduced in 1989.

However, it’s difficult to make such pronouncements with confidence, owing to a rare and refreshing feature of the campaign — a complete absence of opinion polling.

For what they are worth in such an information-poor environment, betting odds suggest the Liberals’ curse of Canberra is likely to persist, with Betfair offering $1.17 on a Labor win against $2 for the Liberals.