The latest opinion polls ahead of Saturday's general election suggest that Ms Clark's opposition Labour Party has a lead of six to eight points over the right-wing National Party, which has ruled New Zealand for the past nine years.
Crucially, the polls also indicate that Labour and its coalition partners, the Alliance Party and the Greens, could win enough seats to form a majority centre-left government under the complex system of proportional representation introduced at the last election in 1996.
The result this time is far from a foregone conclusion, not least because of the permutations thrown up by the electoral system. In 1996, it took eight weeks to form a government; Winston Peters, a maverick Maori politician who held the balance of power, went sailing while the country waited to find out which party he had decided to support.
Saturday will mark the start of New Zealand's second voyage into the murky waters of PR; it will also give the nation a place in the history books as the first Western democracy to hold an election featuring a head- to-head contest between two female political leaders.
Ms Clark, a former political science lecturer renowned as a fearsome intellectual, is hoping to topple the Prime Minister, Jenny Shipley, who was a farmer's wife before entering politics little over a decade ago.
A large chunk of the electorate remains undecided, though, and Mrs Shipley, who deposed her predecessor, Jim Bolger, in a party coup in 1997, is not about to relinquish power lightly. She plans to unleash a blitz of negative publicity in the final days of the campaign in the hope of scaring voters away from Labour.
The two leaders are jostling to occupy the middle ground, decisive terrain in a country that makes a virtue of political moderation and still bears the scars of radical free-market reforms undertaken by Labour governments in the 1980s.
Labour has since reinvented itself as a centrist force and caution is a guiding principle for both parties in this election, making for a campaign bereft of passion or bold ideas. Ms Clark, 49, opposition leader since 1993, is offering economic orthodoxy with a social conscience. Mrs Shipley, 47, has promised tax cuts to safeguard economic growth.
In the final week, both women are concentrating their fire on Auckland, which is New Zealand's biggest population centre, with nearly one-third of the country's 2.8 million voters.
Yesterday Ms Clark crisscrossed the city, visiting a school in the southern suburb of Mangere, a deprived area with a mainly Maori and Polynesian population, and then returning to her constituency, Mount Albert, for a lunchtime walkabout at St Luke's shopping centre.
Mrs Shipley is more outgoing than the cerebral Ms Clark, but she has made a string of mistakes during her two years in office, engaging in open warfare with Mr Peters, her deputy, whom she then sacked, and failing to foresee the impact on New Zealand of the Asian economic crisis.
Ms Clark's advisers visited Britain after Tony Blair'selection victory in 1997 and she has borrowed some of New Labour's strategies, including a "pledge card" containing her party's key promises.
But, as she pointed out in an interview with The Independent yesterday, there is one big difference between the two campaigns.
Mr Blair won a landslide victory with 41 per cent of the vote. Under New Zealand's PR system, Ms Clark, who is polling at about 42 per cent, must keep her fingers firmly crossed for the chance to govern after Saturday.Reuse content