"We have a policy; we don't need an external committee to tell us what our policy is," Mr Abbott told ABC TV when asked directly if he'd nominate someone.

The Liberal leader said rather than appointing new committees Ms Gillard should use cabinet to determine government policy. He had previously demanded the government release "specific terms of reference" for the multi-party group.

Ms Gillard today said it would be "so disappointing" if the opposition refused to participate.

"The reference group will go ahead," she told reporters in Brisbane, before again calling on Mr Abbott to stop playing politics, "and work with others through the reference group to get an effective solution".

Labor's multi-party reference group will consist of three government MPs, two Greens senators and two crossbenchers.