"Obviously we don't know at this stage whether the winner is a local or someone passing through - it could be someone on holiday."
The jackpot is one of the biggest to be won by a single Big Wednesday winner in recent years.
The biggest ever prize, $36 million, was won by a family syndicate in Masterton in 2009.
Last September in Tauranga, a young man who described himself as a "typical Kiwi bloke" won the big prize after he went to get a haircut and found that the barber was closed.
He decided to use the money on a Big Wednesday ticket.
Big Wednesday jackpots
June 2009: $36m, Masterton
Sep 2012: $27m, Tauranga
Jan 2013: $15m, Hastings
Feb 2006: $13m, Thames
Nov 2006: $12m, Wellington
March 2012: $11m, Auckland
Sep 2010: $10m, Reefton