‘If I wasn’t, I’d still go through with it’: ex-deputy PM raises then rejects doubt about whether he’s father of mistress’s baby

An affair that led to the resignation of Australia’s deputy prime minister took a bizarre twist on Sunday after he questioned the paternity of the baby carried by his partner and former aide.

Barnaby Joyce quit and moved to the backbenches last month after his affair with the younger ex-member of staff made headlines for weeks and raised questions about whether he had breached ministerial rules.

The scandal led Prime Minister Malcolm Turnbull to impose a ban on sex between ministers and their staff, in an overhaul of the cabinet code of conduct.

Joyce was the leader of the National Party – which rules alongside Turnbull’s Liberals in a governing coalition – and his resignation appeared to end the saga for the embattled government.

The coalition has a wafer-thin parliamentary majority and has been hit in recent months by a series of controversies that has shaken its grip on power.

But the issue flared up again when Joyce – who left his wife of 24 years for the former adviser – told Fairfax Media in an interview published late on Saturday that the identity of the biological father was “a grey area”.