The 33-year-old trained with the Knights on Wednesday morning and the Newcastle Herald understands he has signed a one-year contract.

A veteran of 11 Tests and four Origins, Tupou returned to Australia last month after being released one year into a two-year deal with English Super League club Wakefield.

A Newcastle product, he will add much needed experience to the Knights pack after the departure of Korbin Sims and long-term injury to Pauli Pauli.

A former Australia Schoolboy, Tupou came through the Knights junior system before joining the Sydney Roosters.

He made his first-grade debut against South Sydney in 2004 and went on to play 111 games for the Tricolours. He signed with Cronulla in 2009 and made 123 appearances for the Sharks.

Meanwhile, hooker Rory Kostjasyn and prop Pauli Pauli will miss at least the opening six games of the season.

Kostjasyn on Tuesday had the first of two operations on his throat to repair the Cricoid cartilage in his windpipe. The first stage was a success but he will undergo further surgery in early March.

Pauli has started off-field cardio training after receiving a favourable report from a specialist.

The 22-year-old, who dislocated his hip in a seven car pile-up on the M1 last month, is expected to be sidelined for 10 weeks.