Liberal frontbencher Kelly O'Dwyer says she will not be distracted by the competition as another prominent gay rights advocate lines up to challenge for the federal seat of Higgins.

Yarra Glen footballer Jason Ball, the first openly gay Australian rules player, will run against Ms O'Dwyer as the Greens candidate in the Melbourne seat, previously held by former Howard government treasurer Peter Costello.

Greens Leader Richard Di Natale has warned Ball will give the safe Liberal seat a "good shake" at the next federal election.

"If we don't get over the line this time around, beware the next election," Senator Di Natale told ABC's Insiders program on Sunday.

The announcement comes days after Labor selected gay rights advocate Carl Katter, the gay half-brother of independent MP Bob Katter, as its candidate for Higgins at the next election.

Ms O'Dwyer told reporters in Melbourne she would not be distracted by those running against her.

"I am there to do my job to the very best of my ability," she said.

"I get out and about in my community and I think I represent their concerns to the nation's parliament."

Both candidates will face a tough fight against Ms O'Dwyer, who holds the seat with a 10 per cent margin and supports gay marriage.