The Mole: League hard man Ian Roberts calls for player fines of up to $150k for head high tackles

Former rugby league hard man Ian Roberts believes the NRL needs to punish players like never before if it is serious about stopping head knocks.

Roberts - who was concussed countless times in a long and distinguished career in the 1980s and '90s - is an expert on the subject.

Medical reports have revealed that Roberts, now 55, has scarring on the brain as a consequence of his many battles in the front row.

And he says the NRL's clampdown - although criticised by some as over the top - is not strong enough and not the answer.

"You've got to fine these blokes like they have never been fined before," the former Souths, Manly, Cowboys and Kangaroos prop told Wide World of Sports.

"Any avoidable contact to the head has to be penalised where they feel it most - in the hip pocket.

"Sin-bins and send offs are only creating an unfair advantage, plus they ruin the game for supporters.

"If you started fining the players financially - and when I say financially I'm talking a percentage of their salary between five and 15 per cent - players would soon adjust that style of play.

"They would be looking at somewhere between $10,000 to $150,000 for a offence.

"Instead of the old six weeks for head high shots, fine them say $100,000. They won't do it a second time."

Roberts - widely respected throughout the game as the first player to openly declare himself to be gay during his career - wants the NRL to also take a stronger stance on bad behaviour off the field.

"I believe they should be fined for serious off field incidents anywhere between five and 15 per cent.

"Hit them in the pocket, deep in the pocket and I'm sure they'll take notice then," he said.