Munro's final six took him to 50 and nailed the win, which dislodges Sri Lanka from top of the world lT20 team rankings.
Only India's Yuvraj Singh with his 12-ball effort against England at Durban in 2007, stands ahead of Munro.
Sri Lanka needed early wickets to have much chance of defending their total, but Guptill and Kane Williamson buried that hope.
They had 58 up in the first four overs and Guptill had hit five sixes before touching a catch behind off Perera for a 25-ball 63.
There was no respite as Munro continued his pitch for the No 3 job at the world T20 in India in March, slapped his second ball deep in the long on crowd.
He followed that with three more sixes inside his first seven deliveries in a hectic assault.
Munro, on his home ground, simply carried on in a tremendous display of hitting. Williamson finished unbeaten on 32 off 21 balls.
Sri Lanka's bowlers had no answer and head home licking their wounds from a tour in which they lost the test series 2-0, and the ODIs 3-1.
Angelo Mathews saved his best innings till last to pull Sri Lanka to 142 for eight earlier, having been sent in.
It hasn't been a particularly productive tour for the classy batsman but Mathews struck a fine unbeaten 81 off just 49 balls, the highest of his three T20 half centuries
New Zealand generally bowled tidily but too many Sri Lankans played airport shots - mentally appearing to having packed their bags for home.
They also lost wickets in clumps two in seven balls, three others in the space of 13 deliveries.
Experienced opener Tillakaratne Dilshan looked likely getting to 28, although over-reliant on his patented Dil-scoop shot on one knee. He tried once too often and reverse swept a catch to short third man off medium pacer Grant Elliott.
Sethan Jayasuriya took 10 balls over three while Milinda Sirawardana, one of the finds of the tour, as caught at long on off his first ball.
Captain Dinesh Chandimal played his second dopey shot in two T20 innings, slogging at spinner Mitchell Santner and edging a catch to short third man for 2.
Kithuruwan Vithanage, unsighted since the second test at Hamilton just before Christmas, gave long off a catch off his third ball.
Only Mathews stood tall, getting to his third T20 half century with a clever upper cut over short third man. It took him 31 balls and without his input Sri Lanka would have been in a sorry state.
Mathews ensured 25 came off the last two overs of the innings with smart and powerful hitting.
The pick of the New Zealand bowlers was unheralded Grant Elliott. The hero of the World Cup finished with four for 22, his best T20 figures, off his four overs of seemingly innocuous little seamers but was the chief beneficiary of some slack batting.
Five New Zealand overs conceded double figures, one each from speedster Adam Milne, left armer Mitch McClenaghan, who did a good job, and spinner Mitchell Santner, while 31 came from Trent Boult's last two overs, as Mathews cottoned on to the short straight boundary and cleared the infield ring.
SCOREBOARD
WAGONWHEEL
MANHATTAN
