Disability campaigner Hollie Hughes has toppled sitting Liberal Senator Concetta Fierravanti-Wells to take out top spot on the party's NSW Senate ticket.

Hughes, an autism support advocate based in Moree, held off the International Development Minister in a tight contest on Saturday to claim first place in a preselection ballot.

May still top Senate ticket: Concetta Fierravanti-Wells. Credit:Andrew Meares

Fierravanti-Wells is the only sitting NSW Liberal senator up for re-election this year.

There is some speculation Ms Hughes could relinquish top spot and swap places with Senator Fierravanti-Wells, but this has not been confirmed.