The Nationals have descended into a bitter brawl over the party's federal presidency, with its annual conference marred by infighting and confusion.

Former Howard government minister Larry Anthony was expecting to waltz into the influential job given he was running unopposed after the favourite, West Australian Dexter Davies, was forced to withdraw from the race.

Former MP Larry Anthony listens to debate at the Nationals federal conference in Canberra on Saturday. Credit:Alex Ellinghausen

But Mr Anthony's opponents – who believe his mining company ties will damage the party and hurt Agriculture Minister Barnaby Joyce's chances at the next election – mounted a last-minute bid to block him.

Mr Joyce is under threat in the New England seat from a resurgent Tony Windsor, the independent who used to occupy the seat.