The Brisbane Broncos have added six players to train and trial contracts, with one roster spot available for the 2022 season.

Train and trial contracts allow players who haven't been able to secure an NRL deal to train with a team's first grade squad over the summer on a figure which is roughly $1,000 per week.

If they impress the coaching staff and club enough over the summer, then the club can opt to contract them, normally on a cut-price, one-year deal.

The Broncos did this last year in securing both Karmichael Hunt and Albert Kelly, while the New Zealand Warriors are just one club attempting it this summer, with Ashley Taylor currently on a train and trial deal with the club.

The Red Hill-based Broncos have brought in former Titan and Warriors' second-rower Leivaha Pulu, Newcastle and Gold Coast five-eighth Tyrone Roberts, former Bulldogs prop Chris Smith, former Manly prop Zac Saddler, and Queensland Cup guns Delouise Hoeter and Ethan Quai-Ward who play centre and wing respectively.

GOLD COAST, AUSTRALIA - AUGUST 07: Leivaha Pulu of the Titans takes on the defence during the round 22 NRL match between the Gold Coast Titans and the New Zealand Warriors at Cbus Super Stadium on August 7, 2016 in Gold Coast, Australia. (Photo by Bradley Kanaris/Getty Images)

According to AAP, the six players are fighting for one roster spot in 2022, and will need to impress over the summer.

Broncos' director of football Ben Ikin also confirmed to AAP that the club are in discussions with discarded Canberra Raiders Dunamis Lui, who has returned to Queensland and otherwise seems destined to spend 2022 in the Queensland Cup.

Ikin also took the opportunity to explain the train and trial contracts.

"It's not a perfect science but you want guys with a mix of natural ability and a competitive desire," Ikin told AAP.

"Sometimes that can diminish later in your career but with the right opportunity it can come bubbling back to the surface.

"The train-and-trial extends that opportunity for guys who are willing to work hard enough."