Former Scotland international Kenny Logan has described the three-week bans which have ruled hooker Ross Ford and lock Jonny Gray out of the rest of the World Cup as a "sick joke".

Ford and Gray were handed the bans for a clearout of Jack Lam at a ruck during the pool victory over Samoa last Saturday which secured the Scots a quarter-final against Australia.

The pair were cited by Australian citing commissioner Scott Nowland over the incident and late on Tuesday found guilty of a dangerous tackle, an initial five-week ban being reduced to three because of mitigating circumstances.

The Scottish Rugby have expressed their “disappointment” at the ban and were considering an appeal pending a review of the full judgement.

Former winger Logan contrasted the ban with an off-field yellow card handed to Australia's David Pocock for a knee in the back of Wales hooker Scott Baldwin and a one-match ban handed to Ireland flanker Sean O'Brien for punching a French opponent.

"This is a sick joke. Pocock clearly knees Baldwin in the back but gets off with a slap on the wrist, and Ireland's Sean O'Brien gets a week ban after a premeditated punch on Pascal Pape in full sight of the referee," Logan told London's Daily Telegraph.

“Two Scottish players with a perfect disciplinary record get a three-week ban for clearing out a player with no malicious intent at a ruck just because he fell awkwardly. There is no level playing field. This is a shameful decision.”

In fear of serious head and neck injuries, World Rugby insists on heavy punishments for tackles where a player is lifted above the horizontal but not helped safely back to ground.

Scotland, who have 48 hours to appeal the decision, face Australia in the last of the four quarter-finals at Twickenham on Sunday.

“World Rugby has totally devalued a World Cup quarter-final,” added Logan, who played 70 times for his country around the turn of the century.