The 26-year-old contested the severity of a three-match ban imposed by the Rugby League's disciplinary committee for a high tackle on St Helens second rower Lee Gilmour and appealed against both the guilty verdict and severity of a seven-match suspension handed out for a stiff-arm tackle on Great Britain team-mate Sean Long.
Both incidents occurred during Wigan's 38-12 home defeat by St Helens in the penultimate match of the regular engage Super League season earlier this month.
Newton not only lost both appeals but, in effect, had the punishment increased because a new three-man panel changed the terms of the suspension.
He will now be banned until April 15, 2006, which means he will miss the first nine rounds of Super League XI and the opening round of the Powergen Challenge Cup.
Since he has already served one match and a pre-season friendly would count towards the suspension, Newton has effectively had his ban increased by two games.
Newton had already been ruled out of the Great Britain squad for the end-of-season Gillette Tri-Nations Series with a hip injury that requires rest.
The appeals committee also upheld the £600 fines imposed on the former Leeds player.