Video referee Sean Hampstead could be relieved of his duties for the third time this year after NRL referees' boss Bill Harrigan admitted to yet another botched call from his officials.

Hampstead's hopes of taking part in Sunday's grand final between Canterbury and Melbourne appear over, Harrigan claiming the decision to award Billy Slater's first try in Melbourne's 40-12 thumping of Manly in Friday night's preliminary final was incorrect.

"Yes, Slater drops the ball and this try should not have been awarded," Harrigan said in his weekly debrief on the NRL website.

It is the second time in as many weeks during the finals series that Harrigan has had to admit to a video referee error following the call to award a crucial try in Manly's semi-final win over North Queensland.

That decision cost Steve Clark and Paul Simpkins any chance of refereeing again during the finals, and it appears Hampstead and Russell Smith could face the same fate.

Hampstead was rested for a week after his controversial decision to award Greg Inglis' match-sealing try in State of Origin I earlier this year.

He was then dropped after incorrectly giving the okay to an obstruction play in a try to Canterbury winger Johnathan Wright in their round 23 win over Wests Tigers.

It could be a case of last men standing for Chris Ward and Bernard Sutton, who are now in line to be in the video review box for Sunday's decider at ANZ Stadium.

The officials for the grand final will be announced on Tuesday.