NRL head of football Graham Annesley says North Queensland were let down by a forward pass call that led to a Parramatta try.

NRL head of football Graham Annesley has conceded that Parramatta's first try in their preliminary final win over North Queensland came as a result of a forward pass.

Annesley claimed the sixth-minute Will Penisini try that came after a pass from Parramatta halfback Mitchell Moses should not have been awarded.

Moses was off balance and weaving his way through the Cowboys line when the pass went towards back-rower Isaiah Papali'i.

The Eels went on to win the game 24-20, sealing a spot in their first grand final since 2009.

"I'm prepared to concede that on balance and on review that the pass out of the hands was forward," Annesley said.

"The thing that determines whether a pass is forward or not, is how the ball comes out of the hands.

"I think what's happened here is because the way Mitch Moses has pirouetted in the tackle, the momentum that tackle has meant the ball has come out of his hands in a forward direction.

"We think that it's forward based on the motion of the hands."

The bunker is unable to adjudicate on forward passes, meaning that referee Grant Atkins had no option to seek a second opinion.

Cowboys coach Todd Payten refused to condemn the officials for failing to pick up on the forward pass, instead lamenting his team throwing away a 20-12 lead in the second half of Friday's game.

The NRL has previously indicated a desire to bring in forward pass technology but has yet to introduce it.