Colin Munro ensured New Zealand continued a stellar home summer on Monday when they thrashed Pakistan by seven wickets with 25 balls to spare in the opening Twenty20 match in Wellington.

Munro was left unbeaten on 49 when a wide by Hasan Ali in the 16th over gave New Zealand victory as they chased down Pakistan's 105 in the clash of the world's top two ranked Twenty20 sides.

It extended New Zealand's winning streak to 13 across all three formats in the past two months including five one-dayers against Pakistan and a series of Tests, ODIs and Twenty20s against the West Indies.

For Tim Southee, the stand-in captain after a late decision to rest Kane Williamson who has a minor injury, everything went according to plan.

"Obviously winning the toss on that wicket and then coming out and taking early wickets was the plan and we were able to do that. We bowled exceptionally well," said Southee who also paid tribute to Munro's role with the bat.

"It was a great knock from Colin. He likes to get on with it and I think he played a mature innings and was able to hammer it home towards the end."

Pakistan captain Sarfraz Ahmed again had to defend a woeful performance by his top order batsmen, which also plagued them in the ODI series, and believed they were well short of a competitive total.

"We're not batting well enough up the order. The new ball was swinging and bouncing, we didn't keep wickets in hand. They bowled very well with the new ball," he said.

"If we had a score of 140-150 it could have been a good match."

After a wobbly start in which Martin Guptill went for two and Glenn Phillips was bowled for three, Munro and Tom Bruce (26) set up the New Zealand victory with a 49-run stand for the third wicket.

After cautiously lifting the score to 34 for two after eight overs, they took 23 off the next 12 balls to reduce the target to under six an over and they coasted from there.

Following Bruce's dismissal, Ross Taylor partnered Munro through to the end with a rapid 22 off 13 deliveries.

Munro's 43-ball innings included three fours and two sixes and he was left a frustrating one-run short of being only the third player behind Brendon McCullum and Chris Gayle to score four consecutive half centuries in Twenty20 cricket.

Pakistan were in immediate trouble after being sent into bat and were four for 22 in the sixth over as Southee led a dismantling of the Pakistan top order.

By the 15th over, Pakistan were seven for 53 and in danger of falling short of their current lowest score of 74 against Australia six years ago, when Babar Khan (41) and Hasan Ali (23) boosted the total with a 30-run partnership.

Southee finished with the best New Zealand figures of three for 13 while Seth Rance took three for 26.