When asked on Wednesday whether he would definitely stay in the agriculture job Mr Joyce said this was getting way too far ahead – the first thing was to win the election.

There has been some speculation that the Nationals leader might move to the infrastructure portfolio, now held by Victorian National Darren Chester. Formerly this was occupied by Joyce’s predecessor as Nationals leader, Warren Truss.

Joyce is currently fighting for his political life, under challenge in his seat of New England from its former member independent Tony Windsor. While a recent Newspoll and internal polling have Joyce ahead, the contest is considered close.

Windsor on Wednesday had to apologise for alluding to the war-related psychological breakdown his one-time friend and supporter and former Vietnam veteran Kerry Schofield had more than two decades ago.

The two fell out over Windsor supporting the Gillard government and Schofield appeared on this week’s ABC Four Corners program on New England supporting Joyce.

This prompted Windsor to say on radio: “I think the character that was there last night, there’s a lot of other reasons for that, which I won’t get into. But the Vietnam War does funny things to people and, anyway, that’s another story.”

Windsor said he had called Schofield and apologised for his choice of words.

“They were an unfortunate choice of words and I apologise for that unreservedly. I’ve been a great supporter of Mr Schofield and his family for many years, and it wasn’t my intention to cause him distress or personal offence,” Windsor said.

“We’ve never had harsh words. He was a close friend of mine since school days, and we’ve shared moments of distress in both our families for over 40 years. It is unfortunate when politics comes between two friends.

“I’m a great supporter of our veterans, and it’s important to recognise their contribution to our country.”

Joyce, appearing in the first of the leaders' end-of-campaign addresses at the National Press Club, on Wednesday announced several measures to give rural and regional students better access to education.

They include A$83 million to ease the conditions for their income support, $24 million for new tertiary scholarships for STEM studies, and $44.7 million to increase the additional boarding allowance for low-income families.

An independent review would be held into educational access for rural and regional students to examine how to “bridge the divide” that exists between them and city students.

A re-elected government would also provide $100 million for upgrading the Outback Way road, which runs from Western Australia to Queensland. Joyce also announced that a regional investment corporation would be established to be the single administrator for the $4.5 billion made available in agriculture and water resources financing and concessional loan initiatives.

This does not involve any new money but would mean the lending would be administered by the Commonwealth rather than the Commonwealth providing the funds to the states to administer.