Culhane made his international test debut at the age of 27 on 4 June 1995 during the 1995 Rugby World Cup. The match, against Japan was won 145–17 and is the largest winning margin for an All Blacks side. Culhane amassed 45 points during his debut, a world record for first class test rugby that still stands today, slotting 20 of 21 conversion attempts and scoring a try.[citation needed] He lost his place in the starting line-up for the next match to first-choice Andrew Mehrtens. He then went on to win just five more caps. He currently coaches Rugby Southland in the New Zealand National Provincial Championship.