Wales rugby union coach Shaun Edwards has pleaded with the referee in tonight's Six Nations clash with England to beware of the visitors illegal tactics in Cardiff.

Edwards has accused the English of deliberate obstruction of players off the ball when they attack.

He says it is similar to strategies employed in rugby league.

"It's also important that there's no obstruction of their defensive plays up ahead of the ball because when you watch rugby league games, there's a lot of tries disallowed in rugby league when they go to the TMO," said Edwards.

"If there's been any obstruction ahead of the ball, it is generally done for obstruction." 

For their part, the England setup has refuted those allegations.