New Zealand posted their biggest winning Test margin when they demolished Zimbabwe by an innings and 301 runs on the third day of their one-off Test at Napier's McLean Park on Saturday.

NZ players celebrate their victory. Pic/AFP

After starting the day at 392-5, New Zealand added 103 in 18 overs, giving BJ Watling time to notch his maiden Test century before declaring at 495-7.

Man-of-the-match Chris Martin then lead a bowling attack that routed Zimbabwe twice in the same day -- first for the tourists' lowest Test innings of 51 followed by 143 in their second innings.

The winning margin was seven runs better than New Zealand's previous record of an innings and 294 runs set in 2005 and also against Zimbabwe.