NSW and Manly back-rower Anthony Watmough is out of the final State of Origin clash on July 9 after failing to have his grade-two dangerous throw charge reduced at the NRL judiciary on Thursday.

The three-man panel of Don McKinnon, Paul Whatuira and Bob Lindner upheld the grading at Rugby League Central and Watmough will miss four matches.

Watmough was slugged with the charge after lifting Queensland prop Nate Myles into a dangerous position just after halftime in Wednesday's Origin clash at ANZ Stadium.

The 31-year-old was facing three games on the sidelines, with an early guilty plea.

He will now miss Manly's encounters with Cronulla on Saturday, the Sydney Roosters and Canterbury in rounds 16 and 17 respectively and the Wests Tigers.

It is the second time a Blues player has faced the judiciary 24 hours after an Origin clash with Josh Reynolds fighting and winning his appeal against the grading of a similar charge in game one.