I don't think this was summoned up by NCOs or COs in the same manner as the Japanese...but rather would be modeled by a different strata of HOB DRM....which might very well be 'treat as Japanese.'
A15.1 HOB TABLE: * Treat as Berserk if: Japanese, Gurkhas, Partisans, Fanatics, Commissars, SS vs Russians, or subject to No Quarter (A15.5)
Which is another reason why treating Maoris as Gurkhas might work.
But I am less convinced that granting them HW ability is warranted.
Edit:
After some further thought, it might be interesting if the Maori were capable of some reckless charging in scenarios set prior to May 1943. (Due to a number of reasons, the performance of the Maori battalion in Italy was less remarkable.)
A simple SSR could permit additional Maori units (treated as Gurkha per SSR) in the same/ADJACENT Location to go berserk per A15.41. This would remove control from the owning player and simulate the spontaneity of a bayonet charge.
Alternatively, a historical charge could be triggered by an SSR-mandated HC (Haka Check).*
In all cases, an SSR should suffice to portray the unique fighting style of Maoris in Greece and North Africa.
*EX: Crete 27 May 1941
"42nd Street" Dr. Monty Soutar, a Maori historian, states that "The instant Maori reaction--a haka followed by a charge made more terrifying for the hapless enemy by the sound of war cries--typified the Maori style of fighting throughout the war." McGibbon, Ian. Ed. The Oxford Companion to New Zealand Military History (Oxford University Press: Auckland, 2000): 309.
In case you're wondering, the Maori didn't pause to do a war dance. A Maori war cry is also known as a haka.
McGibbon's 600-page volume is an excellent general reference. Found my hardback copy in a government book shop in Wellington in 2003. Scored a bunch of other Kiwi military-history titles at the same shop. The army museum in Waiouru has a decent book shop too, but I found the selection in Welly much better.