IGNS has published the following initial details on this earthquake:
recorded by the Institute

Reference Number: 1808572/G
Universal Time: 2001 Oct 21 00:30
NZ Daylight Time: 2001 Oct 21 1:30 p.m.
Latitude, Longitude: 36.67°S 178.84°W
Focal Depth: 33 km
Richter Magnitude: 6.5

Recall that the far-field aftershock forecast from Guam had stated:
The most likely events of Mw>=6 in the next 10 days appear to be:

"New Zealand - North Island 37S 177E
Earthquakes of Mw>=6.5 have occurred within 2 weeks in New
Zealand after each earthquake in Guam since 1930 (with the
one exception of 1975). The probability of such an earthquake
in the next week to 10 days is considered very high. Local
personnel should be on watch, especially on North Island."

-- Far-field aftershock forecast after Guam event (Mw 7.3, 12 October, 2001)

This event lies near the southern Kermadec Islands, recall also that
the far-field forecast from the Banda Sea earthquake (Mw 7.5, 19 October, 2001)
had stated:

"The most likely events of M>=5 in the next 10 days on the
basis of history and far-field triggering theory appear to be:
...
Southern Kermadec Islands"

--Far-field aftershock forecast from Banda Sea, October 19, 2001

Richter Magnitude: 6.5

280 km north-east of Ruatoria

Reported felt at Whakatane. Also likely to have been felt widely on
the Raukumara Peninsula.

• Large earthquake in New Zealand