The deputy Nationals leader, Bridget McKenzie, has voiced strong support for her former leader Barnaby Joyce, declaring the MP is “back in the saddle” making contributions that are “compelling” and “useful”.

McKenzie made the comments at the National Press Club on Wednesday where she released a report on new integrity measures for Australian sport and flagged further measures to encourage new migrants to live in regional areas.

Her endorsement goes against the grain of growing criticism of the former deputy prime minister in the party. The current leader, Michael McCormack, warned that Joyce would still have to face preselection to recontest the seat of New England after he gave a controversial paid television interview in June trawling over the details of his private life.

Asked who else might make a good Nationals MP for New England and whether Joyce could return to the leadership, McKenzie quipped that Joyce was “always my favourite topic”, in a nod to months of bad press following the revelation of his affair with his former staffer Vikki Campion and his eventual resignation as leader.

“Look, I spent two days with Barnaby in New England in recent weeks and his passion for his community and his desire to deliver real change for the people living in those communities is unabated and as strong as ever,” she said.

“I think when you see his public commentary on drought, when you see his public commentary on live sheep exports, Barnaby Joyce is a significant contributor, always has been.

“He delivered a great amount, not just to regional Australia in his time in the leadership, but indeed to our party room.

“So I think … he’s going on with that behaviour, he’s back in the saddle and his contributions are compelling, as always, and useful.”

Joyce has been a vocal opponent of a group of Liberal MPs’ plan to ban live sheep exports and, after a period of leave in May and June, has made significant contributions on climate change policy, warning on Tuesday that applying emissions reduction targets to the agriculture industry was “nutcase stuff”.

McKenzie – only one of two women in a party room of 22 – defended the Nationals’ record on gender during the event, arguing that the party does not have a “woman problem” because “20 guys elected a woman to be their deputy leader”.

She said in the space of seven years the conservative Victorian branch had gone from only having one female parliamentarian in its first nine decades, to add four new female state parliamentarians.

“I think if you look at the party more broadly at the state level … the leader of the party in Western Australia is a woman, we’ve got Deb Frecklington heading up the [Liberal-National party in Queensland], so I think things are changing.

“And I think it’s important that they do change. But I think at the end of the day we want the best representatives possible for the regions irrespective of their gender.”

On company tax, McKenzie said the Coalition “has the policy setting right” because Australia must have a competitive tax rate. She deflected a question on whether the government would ditch the policy before the next election by saying she was “assuming it will pass” the Senate before then.

McKenzie said the Nationals would continue to pursue their policy of decentralisation. This was not just a matter of moving government agencies to the bush but also encouraging internal migration from Sydney and Melbourne, and “strategic regional immigration policies” to encourage new migrants to regional areas.

The government is considering changes to visas conditions to force new migrants to live outside major capitals.

On sport, McKenzie announced the government would conduct a business case to examine the revitalisation of the Australian Institute of Sport in Canberra and opened applications for a $30m grants program for regional sport infrastructure.