Achurch, 24 was a part of the Rhinos side who were beaten in the World Club Challenge to Melbourne Storm.
Having trained with his new side for the first time today, the 6′ 5″ forward is set to make his Hunslet debut against Doncaster on Sunday.
Director of Rugby Darren Williams said: “Mitch is a former Penrith Panther who signed a 4 year deal with the Rhinos and is seen as a hugh prospect by the Champions, to be able to include him in the lead up to a big game on Sunday is a massive boost to the club.
“With club captain David March very doubtful on Sunday along with Luke Haigh and Steve Dooler‘s retirement from semi professional rugby, it’s a timely boost to the squad as injuries are mounting up. Waine Pryce & David Clayton are both ruled out and we need to check on a couple of others.”