But Grant could not give a deadline on the NRL match fixing probe into 2015 Manly games, saying it was a police matter.
The NRL are co-operating with NSW Police's Organised Crime Squad investigation into two 2015 games amid match fixing claims - Manly's round 16 match against South Sydney and their round 24 clash with Parramatta.
It sparked fears Australian punters were placing lucrative bets on NRL matches with offshore betting agencies that are not regulated so as to avoid detection.
No Australian licensed betting companies reported alarming trends in the lead-up to either match, with all 21 required to alert the NRL if they have any concerns over any matches.
However, odds offered by Caribbean firm Pinnacle on South Sydney defeating Manly by more than eight points in round 16, 2015 reportedly dropped from $1.93 to $1.74 in the two days from when the market opened to kick-off.
South Sydney won the match 20-8.
Pinnacle is one of 60 companies around the world who accept bets on the code but are not signatories to the same integrity agreements with the NRL.
The firm is also reportedly said to have higher betting limits and take more money on Australian sports than its competitors.
But Grant said there was no indication that off shore betting agencies should concern the NRL.
"What I can say is that we have the data - we know what goes on in betting in Australia," Grant said.
"A lot of people say there is an international betting market we need to be concerned about - that is not the data we have got.
"We are talking to the offshore gambling organisations the same way we talk to the onshore.
"(But) it will take time to get through the information and the implications."
Police are investigating reports that up to six NRL players were paid $50,000 each to fix the Manly-South Sydney clash.
The bet involved Souths winning by more than eight points.
Grant did not expect to be able to provide an update on the match fixing investigation for at least another month.
"It's a police matter. Obviously we are extremely concerned about it," he said.
"I suspect this will be a month-long thing rather than a week-long thing.
"These investigations tend to be quite thorough."
NRL boss Todd Greenberg has already claimed that anyone found guilty of match fixing faced a lifetime ban.