Labor is keeping up pressure on Michaelia Cash over her involvement in police raids on AWU offices, but she will be out of the spotlight while she is in Singapore to spruik Australian innovation.
Senator Cash is challenging a court order relating to AFP raids of AWU offices in Melbourne and Sydney over an investigation into a $100,000 donation from the union to activist group GetUp! in 2006.
She avoided questions on the subject during a sometimes farcical clash with Labor senator Murray Watt during a Senate estimates hearing last week.
Labor's workplace relations spokesman Brendan O'Connor says Senator Cash has spent $600,000 of taxpayers' money avoiding courts, and is now arguing she can't answer questions in the Senate because of a police investigation.
"If she is under investigation by the police, then she should go to court and answer the questions subject to the subpoena ... or if she is not under investigation she should answer questions in the Senate," he told ABC television on Sunday.
"This is cannot continue to go on, this obfuscation by the minister and the government.
"The prime minister must act, and intervene and either sack the minister or force her to answer these questions."
Senator Cash, the minister for jobs and innovation, will be in Singapore from Sunday till Wednesday to meet with her ministerial counterparts.
During her visit, she will address Singapore's Smart Nation Innovations Week, where more than 20,000 people will gather to learn about disruptive innovations and the Australian Chamber of Commerce to promote Australia's investment in the appropriate digital infrastructure and innovation to support job creation.
She will also exchange ideas on the promotion of women working in the science, technology, engineering, mathematics and medicine sectors.