Phillips was unbeaten in his 52-ball knock as he hit seven fours in New Zealand’s total of 173 for eight.
Jimmy Neesham swept the runs for New Zealand with a swift 29, which included a six in the sights.
Player of the match in T20I 1 is @glendominic159! Team batting first and a crucial 69* off 52 balls with two CAs… https://t.co/Pvja1XpB01
— BLACKCAPS (@BLACKCAPS) 1658173644000
Ferguson tightened the grip on Ireland with impressive figures of 4-14 as the hosts were bowled out for 142 in 18.2 overs.
Ireland, who had missed out on their first win over New Zealand after losing the final ODI by one run last week, elected to field first in Dublin.
It seemed a solid call when New Zealand opener Finn Allen fell for one in the third over off Joshua Little, who took four wickets.
Martin Guptill (24) followed shortly after being dismissed at long off and Dane Cleaver (five) played only seven deliveries on his debut, a length ball off Little Back.
He took himself 4-14 to help the team put on a total defense but was full of praise for Lockie Ferguson @ GlenDominic159 pos… https://t.co/4th60VUGi4
— BLACKCAPS (@BLACKCAPS) 1658188643000
Daryl Mitchell was also dismissed for five off Curtis Camper, leaving the tourists struggling for 54 for four in the ninth over.
Phillips rooted out Ireland’s threat with his flamboyant stroke-play and New Zealand had an early breakthrough on the field when Mitchell Santner claimed a brilliant catch to dismiss Andy Balbirnie for 12.
Black Caps captain Santner picked up two wickets with the ball to bundle out Ireland for 69 for five in the 10th over.
Camper (29) and Mark Adair (25) gave Ireland dim hope, but Ferguson made sure the chase proved too much for the hosts.
New Zealand: 173-8 in 20 overs (Phillips 69 not out; Little 4-35, Adair 2-49)
Ireland: 142 in 18.2 overs (Ferguson 4-14, Neesham 2-19, Santner 2-36)