Ms Mai, who received 5502 votes, spent $10,781 on her mayoral campaign, with her digital media campaign the largest single item at $5201.95.
Greg Martin came second in the mayoral race with 4106 votes and spent $31,009.11 on his campaign - the most of any candidate across Northland - with advertising at $11,756.27 the largest expense. At the other end of the scale Glenn Chapman - who received 78 votes - spent nothing on his campaign, his return form shows.
Of the Far North mayoral candidates - Wayne Brown, John Carter, Ann Court, Mita Harris, Rueben Taipari Porter, Allan Titford and Sarah Watson - Mr Titford and Mr Porter had not filed their election expenses returns. Mr Titford is serving 24 years' imprisonment for a raft of offences, including rape and arson.
Mr Carter's return shows he spent $10,067.42 and received 9604 votes, with pamphlet printing and distribution at $4308.29 the largest expense.
Incumbent Mr Brown received 2868 and spent $28,568.38, the second-largest of the returns filed in Northland. Mr Brown's largest expense was advertising at $20,834.12.
Under the Local Electorate Act, 2001, the maximum amount of electoral expenses candidates can incur is based on the number of people in the area they seek to represent. All candidates had to file their returns by mid-December. Those who have not done so yet will be given until the end of this month to file a return before the matter is referred to police.
Full mayoral expenses page 4