Paul Tupai, who hung up his Bay of Plenty rugby jersey in October, has signed to join English premier club Northampton Saints.

The 30-year-old forward, who brought up his 100th game for the Bay when the Ranfurly Shield was lifted last year, took advantage of his recent Northern Hemisphere tour with Samoa to impress English judges.

He will play alongside former All Blacks Carlos Spencer and Mark Robinson at Northampton and will be captained by another, Bruce Reihana.

Tupai had considered retiring from all levels of football after the 2005 NPC season but when he was selected for Samoa's squad to tour Australia earlier this year, the 11-season, 115-capped Bay of Plenty stalwart was revitalised.

"They (senior Samoan players) kept talking about these 'gold cards'. I didn't know what they meant, so I asked and they told me as a Samoan international we had a passport to play in England," Tupai said.

As a Manu Samoa international, Tupai is treated as a local player and doesn't have to fit any overseas qualification categories.

It is understood English contracts for Samoa internationals start from $150,000 per season, although players still have to pay for their accommodation and living expenses.

The former Rotorua storeman originally thought he'd be on the field for their Boxing Day fixture with competition leaders Sale Sharks but he wasn't able to get visa documentation to leave Rotorua with his wife Nadine and children Leah, 11, and Connor, six, in time.

Tupai said Northampton coaches Budge Pountney and Paul Grayson were impressed with his uncompromising style and signed him as a blindside flanker.

Northampton currently sit second to last in the Premiership but are on target for a quarterfinal spot in the European Challenge Cup.

Tupai is likely to make his debut against Bristol on New Year's day in front of a packed 15,000 capacity home ground.