In the October election, five people ran for four vacancies on the board and a previous law would have meant the fifth candidate would automatically take Mrs Gray's position.
But local electorate law has sinced changed, forcing the council to hold the byelection.
Frank Minehan, who came fifth in the October election, said he wasn't likely to run for the spot.
"I was well beaten and I'm not a masochist."
He said there were a lot of capable women in Greytown who had run for positions on the Greytown District Trust Lands Trust in October who might be applying. In fact, one nomination has been made so far - Margaret Cole, who did try for a spot on the trust but missed out.
Nominations for the position close at noon on Monday, December 16. Voting for the byelection will be held next year on February 11.