A Nielsen poll released on Monday shows Labor's primary vote has slumped to 31 per cent - its lowest level in almost 15 years.
"A lot of that is off the back of the exposure of the problems with the carbon tax and the exposure of so many other problems with this government," Mr Robb told Sky News.
And the coalition is taking credit.
"The incompetence over the mining tax, the huge debt and deficit ... whose driven that?
"(Opposition Leader) Tony Abbott has, so Tony's in a very strong position."
Earlier this year, Mr Abbott predicted there'd be a people's revolt against the tax. Mr Robb says that's now happened."It is a revolt," he said.
"People have come to realise that a carbon tax is a job destroying tax."
The poll also has Malcolm Turnbull streaking ahead as preferred opposition leader, up to 41 per cent, while Mr Abbott's rating dropped three points to 28 per cent.
But Mr Robb said he backed the current leader.
"This is not a sort of popularity contest," he told ABC TV.
"It is a question of leadership and competence and on that question the coalition is now demonstrably ahead of the Labor party.
"(And) Who's been responsible for that?"
AWU denies the unions are ganging up on Labor
The Australian Workers Union has denied the unions are ganging up on Labor at a time when the party needs their support most.
AWU boss Paul Howes said last week the union would withdraw backing for a carbon price if it cost a single job.
But Mr Howes denies he regrets helping Prime Minister Julia Gillard into the top job.
He's told ABC Television Ms Gillard is the best leader the party's had in a long time and he's confident she'll lead Labor to victory at the next election.
