Barnaby Joyce is facing pressure on two fronts as Labor pushes him on his new infrastructure portfolio while he faces more questions about his partner's appointment to two political jobs.
The deputy prime minister has been facing questions over how his partner and former staff member Vikki Campion left his office last year to take a job with Nationals Senator Matthew Canavan, and then with the party's whip Damian Drum.
Labor also upped the pressure on Mr Joyce on Monday, quizzing him about the decision to spend 40 per cent of the national infrastructure budget in NSW, leaving other states short.
Mr Joyce appeared to stumble on some infrastructure answers in Monday's Question Time, as he included investment in a Sydney airport and inland rail as part of an answer about Tasmanian spending.
"Isn't the infrastructure minister simply not up to the job that he has been given?" opposition infrastructure spokesman Anthony Albanese said.
Prime Minister Malcolm Turnbull also told question time it was up to the Nationals how they allocated their personal staff positions in their share of the government's overall staffing pool.
"The distribution of those staff members between Nationals offices is a matter for the National Party," Mr Turnbull told parliament.
"At no time did the Nationals fill all vacant staffing positions."
Ms Campion is now pregnant with Mr Joyce's child - his fifth - after he split last year from his wife Natalie, the mother of his four children.
Mr Turnbull said Mr Joyce made it clear Ms Campion's employment was not discussed with him or the prime minister's office.
However, the prime minister's office "has an administrative role in informing the Department of Finance of changes", Mr Turnbull said.
A spokesman for the prime minister told AAP Mr Joyce had not breached ministerial standards in regard to the employment of family and partners because Ms Campion was not the deputy prime minister's "partner" at the time of her appointments.
Asked if voters would buy the excuse that Ms Campion wasn't Mr Joyce's partner, Treasurer Scott Morrison said it was difficult to untangle.
"He can't have two partners at the same time and he was obviously still married," he told ABC TV.
"Trying to untangle those sorts of very personal issues and when things start and when things stop I don't think is clear in the most often innocent of circumstances."