Labor's education spokeswoman Prue Car has described union commissioned polling showing Labor's primary vote at more than 100-year lows as a "wake up call," saying people "want us to do a better job".

Speaking to 2GB, Ms Car said Australian Workers Union secretary Daniel Walton and Health Services Union secretary Gerard Hayes were "expressing concern from their members" in releasing the polling. That comment is in direct contrast to her leader Jodi McKay who likened the poll to a "cowards punch" from "faceless men".

"They're expressing concern from their members, and I think that's all they're doing there," Ms Car said.

"I do think that Jodi is working as hard as possible as opposition leader and I think that we all have a responsibility to do the work that is required to hold the government to account."

Ms Car declined to support Ms McKay's comments that the two men were acting akin to Eddie Obeid and Joe Tripodi.

Asked whether she could imagine dumping Ms McKay as leader, Ms Car said: "I've always, always supported the leader".

The Londonderry MP said the bombshell poll demonstrates Labor needs to do better in prosecuting the Coalition.

"This one poll is a bit of a wake up call. We've got to do better, and I'm not really surprised, because people are telling me in the community: 'come on guys, you've got to do better at holding the government to account'. And we've got to take that message," Ms Car told 2GB.

Originally published as 'Wake up call': Labor MP contradicts McKay