Moore was then elected Labour's youth vice-president and proceeded to contest the Labour nomination in the 1977 Mangere by-election following the resignation of Colin Moyle. He was seen as a frontrunner but lost to local lawyer David Lange, who would go on to become Prime Minister in 1984. Several months later Moore then sought to be Labour's candidate in the newly formed Papatoetoe electorate but again missed out on selection against Grey Lynn MP Eddie Isbey. By the time of his second rejection for a candidature in an Auckland seat he had received invitations from Labour Party organisers in 16 electorates elsewhere in New Zealand prompting him to consider moving from Auckland in order to gain re-election to Parliament.