Federal environment department officials will front a Senate inquiry into the solar panel rebate, two weeks after they were withdrawn from an earlier hearing.
The Rudd government angered senators after it pulled senior bureaucrats from an inquiry looking at the impact of its decision to limit eligibility for the solar panel rebate.
The government, in the May budget, imposed an income threshold of $100,000 per household for those seeking the $8,000 rebate to offset the cost of installing solar panels.
The decision angered the solar industry, which warned of job losses and company closures, and environmental groups who said it sent the wrong message about the need to reduce carbon emissions.
But the government has said rebate applications are running at record numbers, at a rate of more than 520 a week.
Opposition senators have vowed to quiz departmental officials, accusing government ministers Peter Garrett and Penny Wong of avoiding questions in parliament.
"Questioning the department is the only way well get to the true facts of the situation," Liberal senator Simon Birmingham said in a statement.
The hearing will be held in Brisbane.
