Hardaker signed for the Rhinos in 2011 from Featherstone Rovers and has gone onto make 154 appearances, scoring 67 tries and 45 goals.
He played in all three Tests for England in their series win over New Zealand last year and was named Man of Steel.
Gary Hetherington, the Rhinos Chief Executive, said, “We have agreed with Zak that the opportunity to continue his career at another club is in both parties best interests.
“Zak has established his credentials as a world class player and at the age of 24 he has so much to look forward to. He has given great service to the Rhinos as a fullback, winger and centre and he will remain part of our squad until a transfer is agreed.
“I have no doubt he will continue to give his best as he always does.”
Hardaker said: “I explained my desire to leave and test myself in the NRL to Gary several weeks ago and I am pleased the club is prepared to release me.
“I have had five great years here and have had so many wonderful times. I will continue to help the team whilst I am here but I am also excited with what the future may hold for me.”
Brian McDermott, Rhinos Head Coach said: “Zak is a special talent and a fierce competitor who will do well wherever he plays. We won’t be quite the same without him, but we’ve come to this decision and he will leave with our best wishes.”