Mr Seselja had a resounding victory in his first preselection battle since 2013.

It is understood he beat out former naval officer Sam Fairall-Lee 178 votes to 47.

John Cziesla has been reinstated as the party's president after he was challenged for the position by James Daniel.

"It is an absolute honour to represent the people of Canberra as a Senator for the ACT, and I am grateful to be re-endorsed by the members of the Canberra Liberals," Mr Seselja said.

"I look forward to continuing to be a strong voice for the ACT in the Morrison government, and building on the more than $1 billion in new investment in the ACT from the federal government."

"Congratulations to Luke Hadfield for being endorsed as my running mate on the Senate ticket, and thank you to all who put their hand up to represent the people of Canberra."

Mr Seselja was unopposed in preselection ahead of the 2016 Federal Election.

He has retained the seat since he won out over Senator Gary Humphries in 2013.

The next federal election would likely be set in 2022. Although it could be held as early as August next year, Prime Minister Scott Morrison has previously said he wouldn't be looking to head to the polls in 2021.