The 22-year-old, who can play at full-back or half-back, will head to Down Under for two years after Saturday's Super League Grand Final.
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But he will remain on the books of the Rhinos and is expected to return to Headingley in 2011.
Rhinos chief executive Gary Hetherington said: “We recognise that Jordan’s opportunities have been limited in his favoured positions of full back or in the half backs because of the presence of world-class players like Brent Webb, Rob Burrow and Danny McGuire at the club.
"This is a fantastic opportunity for him to go and play in the NRL and hopefully he will return in 2011 to put his experience to use with the Rhinos.”
Tansey becomes the second Rhinos player to head to Australia in 2009, after Gareth Ellis agreed a deal with West Tigers.
He has started just 19 of the 52 games with the Rhinos since making his debut in March 2006.
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