The 31-year-old has joined the Super League outfit following stints at North Queensland Cowboys, Parramatta Eels and Gold Coast Titans.
"I'm really looking forward to the 2014 season with the Broncos," Atkins told the club's official website. "Playing abroad in the Super League is something I have always wanted to achieve.
"I'm very excited about playing with such a young and talented squad of guys and although the pre-season has been a bit unorthodox, we will all work hard together and embrace the challenges and opportunities throughout the year.
"I have no doubt I will learn a lot from all the playing group, staff and supporters. Exciting times ahead."
Broncos have signed five more players on season-long loan deals.