He has since passed that psychiatric evaluation, as well as undertaken a final meeting with NRL boss Todd Greenberg and chief operating officer Nick Weeks.
All contact with Hayson has also been severed.
"It was split into two aspects — first and foremost integrity, and then secondly Kieran's state of mind," Warriors boss Jim Doyle said of the playing return.
"Kieran met with the integrity unit for a six-and-a-half hours over a couple of interviews (and) we provided them, right up to Friday, all of his bank statements.
"We also provided all of his betting accounts, Kieran had a few."
Since arriving in Auckland, Foran has been seeing a psychiatrist on a weekly basis and liaising with the Warriors' mental skills coach Aaron Walsh.
His contract was initially ratified on recommendation from the psychiatrist and after clear-the-air talks with the NRL at the Auckland Nines.
Foran said he was happy and grateful to restart his NRL career in New Zealand, the country of his birth before moving to Australia aged 10.
He also acknowledged his dealings with the integrity unit had been tough from time to time, as he attempted to prove his mental fitness to play.
"I guess it's been that added unknown of what the future holds," Foran said.
"It's been a really tough road for me, I owe a lot of people a lot of thanks, I've had great support here in New Zealand."
Warriors head coach Stephen Kearney also welcomed the NRL's decision, saying Foran can now look ahead with a clear mind.
Despite Kearney's previous assurance that Foran would be fully fit by the end of February, he is yet to begin contact or wrestle training in Auckland.
Doyle insisted that, once fit, Foran would have to prove his worth to earn the Warriors No.6 jumper from young gun Ata Hingano.
"Kieran still has to go and finalise that and get selected but we know what he's capable of (and) it's pretty exciting to think about the spine we'll have," Doyle said, referring also to Roger Tuivasa-Sheck, Shaun Johnson and Issac Luke.
"We're also aware we've got a lot of very young players like Ata who are pushing all the time, learning things from Kieran."
- AAP