Federal Labor insists it's only fair that if backbencher Susan Lamb is referred to the High Court over dual citizenship woes then government MPs are sent too.
The Turnbull government is seeking the resignation of Ms Lamb and has threatened to use its renewed majority in the lower house to refer her to the High Court.
Labor frontbencher Chris Bowen says the Queensland MP has clearly taken reasonable steps to renounce her UK citizenship.
"We are very, very confident in Susan Lamb's case," he told Sky News on Monday.
The British Home Office did not accept Ms Lamb's application to renounce her citizenship and she failed to supply them with a copy of her parents' marriage certificate, The Australian reports.
Mr Bowen says Labor is happy to have Ms Lamb's case tested in the High Court, so long as other government MPs such as Julia Banks join her.
Tasmanian Liberal senator Eric Abetz says acting Opposition Leader Tanya Plibersek should use her visit to Hobart on Monday to announce Labor MP Justine Keay is resigning.
"In Tasmania, (former Senate president) Stephen Parry and (crossbencher) Jacqui Lambie did the honourable and decent thing and resigned when it was clear that there was an issue," he said.
