Coaches and players have complained that an experimental offside rule being used in the Confederations Cup is confusing and hard for referees to enforce.

Under the rule, players who do not receive the ball are not automatically offside even if they are standing beyond the last defender.

In effect, the rule allows referees to interpret whether a player is interfering or not.

Tunisia coach Roger Lemerre pointed to an incident in his side’s 3-0 defeat to Germany to illustrate his point of his view.

“Look at the pictures of a free kick taken by Germany, and you’ll see that (Michael) Ballack is in front of the goalkeeper and in an offside position.

“When you know the rule, he is obstructing the goalkeeper’s view and for me he is interfering with play.

“I feel really sorry for the referees. (The classic offside rule) is the only intelligent rule in football. Let’s go back to the simple things.

“If a player is offside, he is offside.”

German goalkeeper Oliver Kahn was another unhappy with the new rule, saying: “I thought I was playing indoor football.”

“I actually thought that we had abolished passive offside, but this new rule is dubious and only complicates things even more,” said the experienced Bayern Munich keeper.

But FIFA President Sepp Blatter insisted the rule was here to stay.

“There has never been passive offside and with this rule we’ll hopefully never hear that expression again.

“It will just take a little time for everyone to get used to the new rule.”