Perth by-election will be tight for Labor

Voters in the federal seat of Perth are set to go to a by-election, on a date to be determined, after sitting Labor member Tim Hammond quit.

PERTH BY-ELECTION

* Inner metropolitan seat based in WA capital

* Boundary change before 2016 election made it more marginal for Labor

* Retiring Labor MP Tim Hammond won it in 2016, by reduced margin of 3.3 per cent

* Liberal candidate Jeremy Quinn won the primary vote (42.3 per cent) but Labor won on Greens preferences

* Previous member Alannah MacTiernan retired after one term

* Held continuously by Labor since 1983, but Liberal seat between 1975 and 1983.

* Likely Labor hold if Greens vote remains in double-figures

* Liberal win would take government's House of Representatives majority to two