"You're obviously gifted, and your talent has been spotted and recognised, hence your invitation here to this camp," Hasler told the players, during his talk on Sunday night.
"It's not just good enough to have the athletic prowess or the skills. Mentally, the mind and the ability to perform good habits will ultimately be the reason you either succeed in rugby league or you fail.
"Success in football is about two things - consistency of performance and consistency of attitude."
Hasler flew over to speak at the camp on Sunday before heading back to Sydney early yesterday morning.
The camp will run for four days ending with two selection games at the Rotorua International Stadium tomorrow.
Rotorua's Taiapua Kapua, 17, who plays his club league for Ngongotaha, said he was enjoying the camp.
"I've been learning a lot of new stuff and I'm enjoying meeting new people," he said.
He said his goal was to continue taking things in from the coaching staff and to make the New Zealand under-18 team.
A good performance at the camp, and during the trial game on Wednesday, will help towards being selected for the New Zealand under-18 side.
New Zealand Rugby League general manager of football Tony Iro said the camp gave young players a shot at representative selection. "First of all, it is an opportunity for our best young players in the country to impress the coaches and to make a New Zealand representative side."
He said they were also pushing the message of what it takes to become a professional athlete.
Iro said it was good having someone of Hasler's calibre and he had shared a good message.
"It is the same message we are saying," he said.
"There is no easy path to the NRL and talent only gets you so far. It is the extra little bit that you can add to that that makes the difference."
The boys are staying at Tui Ridge in Rotorua and are doing most of their training at Puketawhero Park.
Other top coaches and former NRL stars attending the camp this week include Nigel Vagana, Daryl Halligan and Nathan Cayless.