Former Kiwi Ferns rugby league representative and Kauri No 8 Krystal Murray added the conversion.
The Tui replied with a try to former Black Ferns halfback Emma Jensen in the 11th minute. Jensen, who is in her 20th year playing in the competition, sliced through some of the big Kauri forwards from close range. From the kick off the Tui increased the tempo and were rewarded with a try to winger Tori Iosefo two minutes later after good work from co-captain and blindside flanker Hanna Brough and lock Liana Mikaele-Tu'u.
Northland regained the lead with a try to captain and former Black Ferns hooker Te Kura Ngata-Aerengamate in the 21st minute. Murray slotted the conversion from out wide.
Poor defence from Hawke's Bay allowed Kauri winger Savannah Bodman to score in the 24th minute. Murray added the extras to put the visitors ahead 21-10.
Hawke's Bay remained in the hunt when centre Michaela Baker scored in the 28th minute after some quick hands from her inside backs. The hosts closed the gap two minutes later when Black Ferns first five-eighth Krysten Cottrell, who played fullback, scored after another quick hands move.
Black Ferns hooker Forne Burkin gave the hosts a 27-21 lead at halftime with a try which Cottrell converted.
Northland opened the scoring in the second half with a handy penalty kick from Murray in the 45th minute. Kauri regained the lead two minutes later when Bodman used her tremendous pace to score her second try after a clever kick from Subritzky-Nafatali. Murray maintained her 100 per cent success rate at goal with the conversion.
The Tui were back in front at 32-31 after a try to winger Cortez Te Pou in the 55th minute after superb support play from the hosts backs. Three minutes later Tui prop Kathleen Brown had too much pace for the Northland defence and dived over for a try which Cottrell converted.
Northland held the hosts out until the 72nd minute when Mikaele-Tu'u scored a well deserved try which Cottrell converted. This try followed a powerful run from substitute prop Moomooga Palu in which she beat four defenders.
Otago beat Tasman 64-10 in their semifinal.
Scorers:
Hawke's Bay Tui 46 (Emma Jensen, Tori Iosefo, Michaela Baker, Krysten Cottrell, Forne Burkin, Cortez Te Pou, Kathleen Brown, Liana Mikaele-Tu'u tries; Cottrell 3 cons), Northland Kauri 31 (Victoria Subritzky-Nafatali, Te Kura Ngata-Aerengamate, Savannah Bodman 2 tries; Krystal Murray 4 cons, pen). HT: 27-21.