Allen (84 not out) and Seifert (89 not out) made mincemeat of the inexperienced UAE bowlers as the Kiwis overhauled the target of 174 in just 15.2 overs.
This was also the highest partnership in T20s for any wicket.
Earlier, skipper Muhammad Waseem and the promising Alishan Sharafu hit fifties to carry the UAE to a competitive 173 for six.
After opting to bat, UAE lost opener Aryan Sharma early to pacer Jacob Duffy, but Waseem (66 no off 45 balls) and Shrafu (55, 47b) added 107 runs for the second wicket to give their side a solid base.
For the Kiwis, pacer Matt Henry took two wickets while skipper Mitchell Santner and Duffy took a wicket each.
Brief scores: UAE: 173/6 in 20 overs (Alishan Sharafu 55, Muhammad Waseem not out 66; Matt Henry 2/37) lost to New Zealand:
Teams (from):
New Zealand: Mitchell Santner (c), Finn Allen, Michael Bracewell, Mark Chapman, Devon Conway, Jacob Duffy, Lockie Ferguson, Matt Henry, Kyle Jamieson, Daryl Mitchell, James Neesham, Glenn Phillips, Rachin Ravindra, Tim Seifert, Ish Sodhi.
UAE: Muhammad Waseem (c), Alishan Sharafu, Aryansh Sharma, Dhruv Parashar, Haider Ali, Harshit Kaushik, Junaid Siddique, Mayank Kumar, Muhammad Arfan, Muhammad Farooq, Muhammad Jawadullah, Muhammad Zohaib, Rohid Khan, Sohaib Khan, Simranjeet Singh.