Labor fails in High Court bid to challenge Bob Day's replacement

Labor's challenge to the eligibility of Family First's Lucy Gichuhi to replace Bob Day in the Senate amid questions about her Kenyan citizenship has been rejected.

The party made a further submission before a High Court sitting in Melbourne on Wednesday after getting legal advice.

"This is not about Ms Gichuhi, this is about the integrity of the Senate and the electoral system," acting shadow attorney-general Katy Gallagher said.

But the court refused the Labor challenge, with Justice Geoffrey Nettle saying the issue of Ms Guchuhi's citizenship was not new.