Storm skipper Cameron Smith has taken the early guilty plea for a contrary conduct charge and is free to face the Roosters in Saturday's preliminary final.

Smith was fined $1350 for a grade one contrary conduct charge after slapping Parramatta hooker Reed Mahoney in the 30th minute of Melbourne's 32-0 win last Saturday.

The 409-game veteran will line up against the Roosters in a do or die battle for a grand final berth.

Parramatta winger Maika Sivo will miss the opening round of the 2020 NRL season after taking an early guilty plea for a grade one shoulder charge on Storm fullback Ryan Papenhuyzen.

Sivo, who finished the 2019 season as the leading try-scorer, was suspended for one game and also has 80 carry-over points against his name.

Storm coach Craig Bellamy was always confident Smith would be available to take on the Roosters.

"He was whacking his hand and one might have hit the arm and gone up to the head," Bellamy said.

"He was just trying to get him to release the grip."