It was revealed earlier this week that Brisbane had failed to offer Niu a contract past this season, with salary cap restraints stopping the Broncos from being able to formally offer the 19-year-old a new deal.
Following the news, it appears several clubs have taken notice, with the South Sydney Rabbitohs early favourites for the outside back's signature.
It's believed the Bunnies see Niu as a long term replacement for Dane Gagai in the centres, with the Queenslander set to confirm his return to the Newcastle Knights within the next few weeks.
South Sydney have opened a pocket of cap space for next season following the departures of Adam Reynolds, Jaydn Su'A and Gagai to rival clubs, opening the door for Niu to link up with Rabbitohs head coach and former Brisbane assistant Jason Demetriou next year.
Niu has enjoyed a breakout season at Red Hill, scoring three tries in Brisbane's last five games, including a stunning double against Cronulla in Round 16.
Niu would add to an already potent backline, featuring the likes of Latrell Mitchell, Alex Johnston, Cody Walker and Campbell Graham in 2022, with halfback the only real question mark over the Rabbitohs premiership credentials for next year.