Hayson, who is reportedly socially involved with Brett Stewart and former Manly players Glenn Stewart, Kieran Foran and Anthony Watmough, has been linked with placing large bets on at least the Rabbitohs clash.
Hayson has denied those claims, and there is no suggestion any of those players are involved in any match-fixing allegations.
Johns and Hayson once owned six racing horses together and were embroiled in a betting scandal when the latter reportedly won $1 million after betting against Newcastle, in a match where the Knights halfback was ruled out injured late in the week.
The NRL investigated the matter, but both were cleared of any wrongdoing.
Johns' denials came after Manly official Peter Peters said on Sunday the club had long been worried about some of the figures former off-field staff had brought to the club.
"We're concerned at some of the elements that are around our club, that are seemingly welcomed to the club by a certain section of our club' - who are, I might say, no longer with us," Peters told Sky Sports Radio.
"We had a situation where we felt like we should go to the NRL. The concern was about just the types that were gathering."
- AAP