JOHNATHAN Thurston will stay at the Cowboys in what could be the richest deal in rugby league's recent history.

North Queensland officials confirmed Thurston's signing today, 24 hours after the champion Queensland and Australian five-eighth set up all four of the Cowboys' tries in their impressive 24-12 win over last year's grand finalists Canterbury at Bluetongue Stadium.

"It's a big relief. Obviously Johnathan means a lot to this club,'' said football boss Peter Parr at a news conference in Townsville this afternoon.

"We're humbled he has taken less money to remain here.

"It means we've got one of the best players, if not the best player in the world for the next five years.''

He will be at the Cowboys until the end of the 2017 season.

"My last contract was a tough decision, but nothing on this one,'' said Thurston of his latest deal.

"I'm delighted and relieved to get it out of the way so early in the season.

"I've got lifetime friends and best mates here and unfinished business.

"The last few weeks have been tough to come to this decision but it's the right decision for me.''

The contract puts the supremely talented playmaker among the highest-paid players of any football code in Australia.

The Gold Coast Suns' Gary Ablett is thought to be the AFL's biggest earner, on a $1.3 million a season deal at the new franchise, while Italian superstar Alessandro Del Piero stands alone on his $2 million a year salary with Sydney FC in the A-League.

The final details of the contract, which include a range of lucrative third-party arrangements allowed under the NRL's salary cap, were finalised last night.

Thurston is the Cowboys' third major re-signing, alongside representative props James Tamou and Matt Scott.

The 29-year-old turned his back on a rich offers from the Panthers and his former club, the Bulldogs. It's understood that Panthers boss Phil Gould, who put together a deal that included an attractive post-football career, was told of the news over the weekend.

The Panthers were the closest to snaring Thurston, who was the most sought-after player off contract for next season.

He was courted by several clubs, including the Bulldogs, who flew him down to Sydney for a secret late-night tour of the club's Belmore facilities with coach Des Hasler.

Thurston's decision to remain in Townsville will be a huge boost for the Cowboys.

After Saturday night's win over Canterbury, and with Thurston's future still unresolved, Cowboys centre Kane Linnett said the star's retention was an important boost for the playing group.

"JT, he does so many good things - not only on the field but off the field for the Cowboys," the young centre said.

North Queensland coach Neil Henry also said Thurston was "close" to deciding his future.

"My gut feeling all along has been that he'll stay," Henry on Saturday night.

"Until it's done, it's not done but I'm confident the club ... has been able to put something together to enable him to stay at the Cowboys I think there's a bit of clarity about the whole thing now and we will get something this week."