The Nationals are hoping young New South Wales Cabinet Minister Adam Marshall, who has made headlines for his poor driving record, will take the plunge into federal politics if Barnaby Joyce resigns from Parliament.

Key points: Nationals are preparing for life without Barnaby Joyce in the crucial seat of New England

Nationals are preparing for life without Barnaby Joyce in the crucial seat of New England Adam Marshall has harboured ambitions of the prime ministership, but pleaded guilty to a drink driving charge in 2013

Adam Marshall has harboured ambitions of the prime ministership, but pleaded guilty to a drink driving charge in 2013 Some Nationals feel Mr Marshall may be reluctant to leave a state cabinet position to sit on the federal backbench

If Mr Joyce steps down or his party rolls him, the first priority will be electing a new Nationals leader, who is the second in charge of the country.

But another challenge will be keeping the seat of New England.

Mr Joyce had a resounding victory against a field of low-profile candidates at the end of last year.

But if a well-known independent or minor-party candidate steps up, there are fears the Nationals could not be assured of winning the seat again.

If there was a by-election ahead of the next election, this could have implications for the makeup of the Parliament, where the Government only holds a one-seat majority.

The Nationals are also worried about the prospect National Farmers Federation president Fiona Simson could run against them.

She has previously said she would rather stick hot needles in her eyes than contest the seat.

Mr Marshall took over the state seat of Northern Tablelands in 2013.

The popular local member has had ambitions to be the nation's prime minister, and was captain of Farrer Memorial Agricultural High School outside Tamworth.

But some within the state branch of the Nationals are worried Mr Marshall would not want to give up a state cabinet position to sit on the federal backbench, particularly when the Federal Government is facing the prospect of moving into opposition after the next election.

Mr Joyce told News Limited after the by-election last year he had been considering not running.

Personal pressure on Joyce coming to a head

The unfolding crisis over his relationship with former staffer Vikki Campion now sheds more light on the personal pressure Mr Joyce has been under.

Sorry, this video has expired Barnaby Joyce publicly confirmed his new relationship on Tuesday and apologised for hurt caused by the affair.

Many reporters covering the by-election were trying to establish whether Mr Joyce was having an affair, and whether there was any public interest element to the relationship.

The ABC has now confirmed the Nationals were prepared to put up another candidate for the by-election if the story got out.

Mr Marshall is the popular Tourism Minister in the New South Wales Government.

He's increasingly being considered as the best option internally because he is well liked in the electorate and a good parliamentary performer.

He gained notoriety for a string of alcohol and speeding-related driving offences.

The 33-year-old pleaded guilty to mid-range drink driving in 2014.

Another state MP, Kevin Anderson, who represents the seat of Tamworth has also been touted as an option.

Mr Marshall and Mr Joyce campaigned together during the New England by-election, when Mr Joyce visited Inverell.

The pair were both on stage for the crowning of the Sapphire City Queen, a contest for young local women to represent the city as an ambassador.

Mr Joyce went on to win the by-election in a resounding victory over a field of low-profile opponents.