The 30-year-old, one of the longest serving members of the squad having made his debut back in 2001, has signed a two-year deal with the Guinness Premiership club. Carstens, who has eight Test caps for the Springboks, had a deal at Kings Park until the end of 2010. He is currently sidelined with a knee injury, meaning he will not feature again for the John Plumtree's side unless he decides to return in the future.

"It has been a good life for me here in Durban and I have loved being a part of the Sharks set-up for these past 10 years, so it is hard to leave," said Carstens. "But I need to move on and experience a new challenge and get out of my comfort zone. Luckily for me, I will be joining up with a bunch of South African players and of course, Bradley Barritt, who I know from the time he played with me for the Sharks."

Carstens appeared 168 times in Super Rugby and Currie Cup for the Sharks during his time with a total of 13 tries and Saracens director of rugby Brendan Venter was delighted with his signature after losing out on Northampton prop Soane Tonga'uiha. "Sometimes in life things just seem to work in your favour - we are delighted to have signed Deon for next season. More than a world class loosehead on the field, he is also an outgoing and infectious character - exactly the kind of person who will enjoy and enhance the spirit within our squad."

The 32-year-old, capped 66 times by the All Blacks joined the West Country side in December 2008 but recent speculation has linked him with a return to the southern hemisphere. "This is a really hard decision to have made as I've loved every minute of playing at Kingsholm," Somerville explained. "I just feel that now is the right time for my family to be nearer home, particularly with our third child being born just before Christmas."

Head coach Bryan Redpath added, "Greg's contribution on and off the field has been exceptional as you would expect from somebody capped so many times for the All Blacks. The knowledge he's been able to pass on to the younger props coming through has been invaluable and Paul Doran-Jones, Rupert Harden and Shaun Knight are all better players having had the chance to work and train alongside Greg."

Reports in the Australian media suggested that the Force were preparing to table a lucrative offer, allegedly backed by a third party, to lure the 22-year-old to Perth with suggestions that the Reds, who are currently under financial administration with the Australian Rugby Union, maybe forced to cash in on their star player.

However, writing on Twitter, the Wallabies international said, "Just to let everyone know I'm NOT shopping around I'm just trying to concentrate on playing good football. I'm having so much fun playing with my team mates and enjoying seeing the fans support for us so thanks to everyone."

"This is a great result for Tasman," NZRU chief executive Steve Tew told NZPA. "They have worked hard to turn their fortunes around and it is particularly impressive to do it in what is a challenging time for the sport and other provinces. I would like to make particular mention of (chief executive) Peter Barr, who has steadied the ship by cutting costs and driving the union forward."