A constitutional law expert suggests changing rules on enrolling to vote could benefit the current Government.

A report by the Auditor-General's found pressures on systems led to mistakes in the vote count, such as a rushed final check of the official results.

Justice Minister Paul Goldsmith has proposed stopping people enrolling to vote on election day to slim down numbers of special votes.

Otago University's Andrew Geddis says people showing up that way tend to vote left.

"The special votes every election deliver more seats to the left parties than the right. So if you end election day enrolments, you'll help the right - which is why Paul Goldsmith is so keen to do it."

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