A second federal government minister has played down the possibility of a royal commission into "horrendous allegations of corruption" in the building industry.
Employment Minister Eric Abetz says the coalition is still considering its options for an inquiry, while Labor is calling for terms of reference to be made public.
Reports of improper deals, including bribery and kickbacks, by construction sector union officials saw Prime Minister Tony Abbott slate a full inquiry, with a royal commission one option.
But Senator Abetz says it is yet to be decided how the claims will be probed.
"These horrendous allegations of corruption clearly show that something is very wrong in our construction sector," he told the ABC on Sunday.
"We're considering the allegations and considering what the appropriate response will be.
"We're not going to be rushed into a decision."
Labor frontbencher Penny Wong says the alleged criminal conduct should be investigated by police, adding the government's plan for a judicial inquiry is bound up in its political agenda.
"What you are seeing is an attempt by the prime minister to attack and smear the entire labour movement with the allegations of criminal conduct of some rotten apples who need to be fully investigated," Senator Wong told Sky News.
On Thursday Treasurer Joe Hockey stopped short of committing the government to a royal commission, but the coalition is united in its call to re-establish the Australian Building and Construction Commission.
"Under our legislation the ABCC would cut both ways, both into corrupt unions and corrupt employers and we believe that is the vital balance," Senator Abetz said.
But the regulatory body, scrapped under the Labor government, has never looked into criminal conduct in the past, Senator Wong said.
