Newcastle forward Korbin Sims has failed to downgrade his high tackle charge at the NRL judiciary on Wednesday night, and will miss Sunday's clash against Penrith. 

Sims disputed his grade two careless tackle during the Pacific Test but was unable downgrade it into a grade one. He will be available for selection the following week.

The Fijian firebrand ironed out Samoan halfback Penani Manumalealii in the 49th minute of the match.

The 22-year-old had nothing to lose by pleading guilty and challenging the grading, with one week the maximum amount of time he would miss. 

Meanwhile, Samoan forward Sam Tagataese has taken the early guilty plea for his headbutt to Fijian prop Kane Evans, and will miss Cronulla's Monday night match against Parramatta.