A Talbot Mills (formerly UMR) Poll taken between August 31 and September 6 had Labour at 45 per cent and National at 26, with Act on 13. The Greens and Te Paati Māori were on 6 and 2 per cent respectively.
The worst poll came from National's own pollster, Curia. A poll taken for the Taxpayers Union between September 5 and 9 had Labour on 45.8, with National languishing on 21.3.
Both of those polls also had Seymour beating Collins as preferred prime minister.
Collins has had a tough fortnight as leader, rocked by speculation a leadership coup might be imminent.
Last week, she vowed to fight on as National leader, saying she will never resign from the job.
"I feel very secure in [the leadership] and I know the caucus is working very hard with a common goal of holding this Government to account," she said.
"Once things start getting under 35 per cent people start saying 'Can we win?' And I know I am putting a mark up there which at some stage in the future, if I am successful this time, that people will say 'Well, you set that mark," Collins said in that interview.