Both of Southland's general electorates are being treated as foregone conclusions in the final week of the campaign, even as the Electoral Commission reports a lower share of eligible voters on the roll than at the past two elections.

The Spinoff's ranking of all 71 electorate races, published on Monday, places Invercargill and Southland in its bottom tier of "safest seats", picking National's Penny Simmonds and Joseph Mooney to be returned without drama on Saturday.

The 2023 results explain why. Ms Simmonds won Invercargill with 20,819 votes, a majority of 9874 over Labour's Liz Craig, and National took 42.5 per cent of the electorate's party vote. In Southland Mr Mooney polled 23,231 votes and a majority of 17,211, with National on 48.3 per cent of the party vote.

This time Ms Simmonds faces Labour's Janice Lee, the Koha Kai founder, and the Green Party's Dave Kennedy, who contested Southland in 2023. Mr Mooney's challengers in Southland include ACT list MP Todd Stephenson, NZ First's Jason Herrick, Labour's Peter McDonald, Bianca Beebe of The Opportunities Party and Vision NZ's Naomi Maclean.

Nationally the picture is less settled. An Ipsos poll reported by RNZ on Monday has Labour extending its lead and fuel prices entering voters' top three concerns, and the Spinoff's ranking counts far more competitive seats elsewhere.

Chief Electoral Officer Karl Le Quesne told RNZ's Morning Report on Friday that the provisional enrolment rate stood at 93.6 per cent, down from 94.7 per cent at the 2023 election. He said the figure was higher than in 2014 and 2017 but a little lower than 2020 and 2023, and called it "a reasonably healthy enrolment rate" while acknowledging the commission always wanted it higher.

This is the first general election at which enrolment closed before advance voting began, on 25 October, rather than allowing people to enrol and vote on election day. Former Attorney-General Judith Collins warned when the law changed that it would cut enrolment; RNZ calculated another 40,000 enrolments would have been needed to match 2023's rate.

Mr Le Quesne said the commission had largely succeeded in persuading about 450,000 habitual late enrollers to sign up early. Among 18 to 24-year-olds, 74.2 per cent are enrolled, short of 77 per cent in 2023 but up from just over 50 per cent in July after a youth campaign added about 85,000 names.

Of 603,968 voters of Māori descent, 55 per cent are on the Māori roll and 45 per cent on the general roll, up from 567,012 in 2023. Southland's Māori voters are in Te Tai Tonga, the largest electorate in the country.

The commission also disclosed on Friday that a fault in its enrolment system had asked up to 6800 applicants with residence-class visas for immigration information they did not need to supply. Mr Le Quesne said the commission was treating the matter with urgency, contacting those affected to confirm their applications were sufficient, and that anyone eligible who applied before 25 October could still cast a special vote.

Advance voting continues at voting places across Invercargill and Southland until Friday 6 November. Election day is Saturday 7 November, with preliminary results from 7pm and official results due on 27 November.