The Telegraph also revealed alleged Instagram messages exchanged between Okunbor, 23, and the 17-year-old schoolgirl.
"Having a good stalk?" the girl asked the NRL player.
"Yeah had to have a good look," he alleged to responded before asking "What are we doing tonight?".
The girl replied back "You" and a wink emoji.
Okunbor allegedly asked the girl "we're (sic) you at the school today" and she provided a photo with herself, Okunbor and another Bulldogs teammate.
NRL CEO Todd Greenberg told NRL.com the Bulldogs duo face "significant sanctions" if they have found to have taken part in the "completely unacceptable" conduct allegations levelled at them.
"Our players have no greater social responsibility than promoting respect for women," Greenberg said.
"Part of being a first-grade player is being a role model. Respect for women is a fundamental aspect of our training courses from rookies to elite players.
"That's why we took immediate action in provisionally suspending both players allegedly involved in the matters under investigation.
"We didn't hide behind the investigation. The Bulldogs and the NRL made the decision to proactively stand down the players to send a very clear message that allegations of this nature are completely unacceptable and will not be tolerated.
Both players will now miss at least the opening match of the season and have been banned from training.
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'It's disgusting. It's repulsive'
The club is without a major sponsor for 2020 and it was reported on Wednesday the scandal has hit the Bulldogs financially because a potential backer pulled out after being told of the incident.
The Sydney Morning Herald reports family restaurant chain Rashays and the club had agreed on a sponsorship deal worth A$2 million which was set to be announced on Tuesday night.
But after the club informed Rashays of the scandal, the deal was withdrawn, leaving the Bulldogs as the only club in the NRL without a major sponsor on the front of its jersey to begin the season.
Rashays owner Rami Ykmour told the Sydney Morning Herald his company would still back the Sydney club if the contracts of Okunbor and Harawira-Naera were ripped up.
"It's a shame two players could wreck it for everyone," Ykmour told the Sydney Morning Herald.
"It's disgusting. It's repulsive, to be honest. That's something else. If they sack them, I would stand by the club and the NRL's decision."
At the NRL season launch last week the Bulldogs were the only side without a jersey sponsor. The side play in the competition's opening game against the Eels tonight.