The NRL won't register the four-year contract of Newcastle Knights recruit Russell Packer due to behavioural breaches.

The St George Illawarra Dragons have announced the signing of Russell Packer to a two-year playing contract following approval this week from the NRL.

Packer, 26, will officially join the Dragons squad for 2016 and 2017 whilst at the same time, continuing to maintain his commitment to Dragons Community programs and his personal and professional development outside of rugby league.

“I am very thankful and grateful for the opportunity to return to the NRL with the Dragons,” said Packer. “I have learned a great deal and changed a lot over the past two years and I couldn’t be happier with where things are at for me and my family.

“My family and so many people at the Dragons and the NRL have shown great faith in me and I look forward to repaying them for their belief and support over the coming seasons both on and off the field”.

In May, Packer was registered to play with the Illawarra Cutters in the NSW Cup, and he finished the season as the team’s Captain and “Player of the Year”.

In August, Packer was cleared to train full-time with the Dragons NRL squad, which was around the same time that he began studying a Bachelor of Business at University, following completion of a Certificate IV in Community Services at TAFE Illawarra in the first half of the year.

Read more at dragons.com.au