The Electoral Commission said 207 voting places were open on Monday, with that number rising to more than 2,300 on the November 7 election day.
Overseas voting opened on October 21.
Public polling has swung sharply in recent days, underscoring the absence of a clear frontrunner under New Zealand's mixed-member proportional system, where coalition deals are often needed to form a government.
A 1News-Verian poll published on October 20 put the ruling centre-right National Party at 32 per cent and opposition Labour at 27 per cent, while a Post/Freshwater Strategy poll published a day earlier had Labour narrowly ahead on 28.7 per cent to National's 27.6 per cent.
In both surveys, the smaller Opportunity party was polling around or above the five per cent threshold needed to enter parliament, making it a potential kingmaker.
The start of voting comes just hours after enrolment closed at midnight on Sunday, a deadline that has become one of the campaign's most contentious issues.
Unlike in previous elections, voters can no longer enrol or update their details during the voting period, meaning people not enrolled by the cutoff cannot cast a vote in this election.
Critics say the earlier cutoff could deter participation, particularly among groups that are harder to reach.
The Human Rights Commission said last year that ending election-day enrolment was likely to unjustifiably restrict participation and would disproportionately affect under represented groups.
As of October 21, 3,729,667 people were enrolled to vote, already above the final 2023 total of 3,688,292, when the enrolment rate was 94.7 per cent, according to the Electoral Commission.
