Other expenses including travel and minor equipment, and having operating computers and phone services cost over $50,000 each.
Printing ballot papers, stationery and postage cost just under $50,000.
Whether it was the effectiveness of the Electoral Commission's message or the mood of the electorate, in the pre-election week, early voting figures were more than double those for the general election last September - more than 5500, or 10 per cent of enrolled voters.
New Zealand First leader Winston Peters won by a majority of 4441 in a seat that had been won by National just six months earlier with a majority of 9000.
More than 30,000 of the Northland electorate's 45,846 enrolled voters participated in the controversial byelection, bucking a national trend where byelections tend to attract far fewer votes than general elections.
Overall, 65.6 per cent (30,161) of the 45,846 enrolled in the Northland electorate voted in the byelection, very close to the 35,056 people who went to the ballots in the 2014 general election. Electoral officials say there was also a spike in new enrolments for the general roll after the Northland byelection was announced in February.