The family of a Northland woman whose early vote won't be counted following her death are calling for a change to electoral law.

Mehara Tamaki, 19, died suddenly last week, but her relatives say her vote should still be valid.

She was known for her passion for politics, and was excited to finally be old enough to cast a vote.

The 19-year-old was at the polling booth the day early voting opened last Monday.

But her vote is now invalid, because she died suddenly in her sleep that same night.

"She'd made a goal to be able to eventually go out and vote and she achieved that vote on Monday 11 September and that goal was sadly stripped from her," family friend Makoare Hoterene says.

The electoral act states if a person votes but dies before election day, their vote isn't counted.

Word spread among Ms Tamaki's family as she lay in state at a marae in Whangarei.

They've now launched an online petition calling for a law change not only to honour her vote, but also her work as a youth advocate.

"She was made a national executive of the Mana Party so it was evident that she was going to one day be pursuing a career in politics," Mr Hoterene says.

The Electoral Commission says it understands there's sadness and disappointment around Ms Tamaki's early vote but says under law it cannot be counted. However, if someone was to die on election day itself, their vote would still be valid.

Associate Justice Minister Mark Mitchell says the issue will form part of a post-election review.

"The Justice and Electoral Committee will call for submissions and begin an inquiry probably around April or May next year," he says.

He agrees it's an important issue that shouldn't be ignored.

"I'd be very surprised if there wasn't cross-party support for having a serious look around eligibility and to ensure that we can avoid cases like this again."

Newshub.