Colin Munro blasted New Zealand's fastest Twenty20 half century to surpass a mark set by Martin Guptill earlier in the innings as the hosts swept their two-match series against Sri Lanka with a nine-wicket win in Auckland last week.

The mayhem in the second T20 is likely to send chills down the spine of Pakistan, who are New Zealand's next opponent in a T20 series.

Guptill first rewrote the record books when he took just 19 deliveries to bring up his eighth half century in the shortest form of the game before he was eventually dismissed for 63 after smashing six boundaries and five sixes.

His mark was then eclipsed by Munro some 20 minutes later when the left hander hit his seventh six to take New Zealand to 147 for one, the hosts chasing down Sri Lanka's 142-8 total at Eden Park in just 10 overs.

Munro's half century came off 14 balls, the second fastest in international cricket behind India's Yuvraj Singh (12 balls). He hit one four along with his seven maximums to finish unbeaten on exactly 50.

The swashbuckling New Zealand side takes on Pakistan in a three-match T20 contest starting January 15. The series will be followed by three ODIs with the contest promising to produce a few more fireworks and perhaps some headaches for bowling attacks.

New Zealand v Pakistan schedule:

Jan 15: 1st T20, Eden Park, Auckland

Jan 17: 2nd T20, Seddon Park, Hamilton

Jan 22: 3rd T20, Westpac Stadium, Wellington

Jan 25: 1st ODI, Basin Reserve, Wellington

Jan 28: 2nd ODI, McLean Park, Napier

Jan 31: 3rd ODI, Eden Park, Auckland