Labour has lost four list MPs and, critically for the party that aimed to have a 45 per cent female caucus, three were women.
The party's provisional caucus currently has 12 women, which at 37.5 per cent of the total, is below the threshold.
Labour's crippling election result on Saturday means women list MPs Carol Beaumont, Maryan Street and Moana Mackey, as well as Chinese-New Zealand man Raymond Huo, are unlikely to make it back into Parliament.
Before the 2014 election, the Labour caucus had 41 per cent women MPs - 14 out of 34.
In November last year, when the party announced its target of 45 per cent women MPs after the 2014 election and 50 per cent in 2017, Labour leader David Cunliffe said the goal wouldn't be hard to reach.