* Melinda Pavey - the water, property, and housing minister is the only MP to confirm her nomination for the top job, on Monday saying she was encouraged by the support of her colleagues. Raised on a dairy farm, the former broadcast journalist and small business owner succeeded former party leader Andrew Stoner as the member for Oxley in 2015 and has worked as roads and maritime minister.

* Paul Toole - the deputy NSW Nationals leader and Bathurst MP is also reportedly seeking a promotion. Mr Toole - a former school teacher and mayor - was elected alongside John Barilaro in 2011, and has said he is deliberating "how best I can serve our party" over the next 24 hours. Currently minister for regional roads and transport, he has also held the racing, local government, and land and forestry portfolios.

* Adam Marshall - the agriculture minister is yet to show his hand, but has also been touted as a potential successor. Also a former journalist and mayor, he was elected to the Northern Tablelands - the state's third largest electorate - in 2013. At 37, the Gunnedah local is the youngest potential contender in the field.

Australian Associated Press