A by-election was held for the New South Wales Legislative Assembly electorate of Heffron on 23 June 1990 because of the resignation of Laurie Brereton (Labor) to successfully contest the 1990 federal election for Kingsford Smith [1] The Labor candidate for the election was Deirdre Grusovin, the sister of Brereton.
[2] The Heffron by-election was held the same day as the Granville and Smithfield by-elections.