Koroisau allegedly snuck the woman into the Blues camp on June 20 - one day before the team was moved to Kingscliff, in northern
NSW, to escape Sydney's rampant Covid outbreak.
The married father-of-two allegedly also met up with the woman on a second occasion, on the day of Game 2, when the team was in a 'bubble' to prevent any potential exposure to the virus.
The woman claims Koroisau gave her 'strict' instructions on how to sneak into camp without being noticed.
The woman, who asked not to be named, said she met Koroisau on Instagram in June, and he quickly prompted her to message him on Snapchat instead.
Over the course of a few days and their two meetings, she 'developed feelings' for him, claiming she fell for his 'sweet, nice, caring' personality.
'I actually started to have little feels for him,' she said. 'He came across like such a sweet nice caring guy who gave me a lot of attention and sweet words.. I definitely got sucked in!'
But she'd also been instructed
not to 'like' or 'comment' on any of his content on Instagram in case his wife saw and got suspicious.
But Koroisau allegedly breached the rules by inviting the woman, who was holidaying in Sydney, into the Blues camp despite the Covid outbreak in the city.
'I was told to message him when my Uber was about to drop me off and walk straight into the lifts, where he would be waiting for me,' she said.
Koroisau was in the elevator when the woman arrived, and ushered her directly up to his room.
They allegedly spent about two hours together before Koroisau told her to leave because he had to return to his teammates - who were all together downstairs.
After 14 days of Quarantine, In addition to juggling three backpacks, Koroisau's wife Amy had her youngest daughter Kalesi strapped to her chest and kept a close eye on her eldest, Miliana, who walked alongside her off the tarmac and toward the shuttle bus.
Amy, who found out about her husband's indiscretion when the woman contacted her on social media last week, travelled with the couple's two young daughters to Coolangatta on the
Gold Coast on Wednesday to join her husband and his team.