NRL referees' boss Tony Archer has admitted Sydney Roosters forward Aidan Guerra should have been sinbinned when he impeded Vodafone Warriors captain Ryan Hoffman in yesterday's fifth-round NRL clash in Gosford.

Hoffman was hunting down a try from a Jeff Robson grubber kick midway through the first half when he was held back by Guerra.

There were calls for a penalty try in some quarters while many other analysts contended Guerra should have been sinbinned at least.

After being referred to the NRL Bunker, only a penalty was awarded to the Vodafone Warriors.

Archer today conceded the wrong decision had been made. Watch his explanation.