She also had a special interest in youth issues and helped set up a youth group.
Mrs McMaster, who has lived in Martinborough for more than 15 years, said she would still contribute to the group.
The by-election will be conducted by postal voting under the First Past the Post electoral system, on Tuesday, May 19, if more than one candidate stands.
Nominations opened yesterday and close at noon on March 23. They must be made on the nomination form available in hard copy from the South Wairarapa District Council office, 19 Kitchener Street, Martinborough.
Registrar of electors for the Wairarapa electorate Philip Parkes urged Martinborough ward residents to enrol or check that their enrolment details are correct, by March 23.
"Only those people who are correctly enrolled will receive voting papers in the mail and be able to have a say in the election.
"This makes it very important for newly eligible electors to enrol as soon as possible and for those already enrolled to check that their details are up to date."
Those already enrolled to vote in the general election are automatically enrolled for the by-election. People can also check at any PostShop, council office or public library.