Richardson said Muralitharan often bends his arm beyond the 15 degree norm even though he feel it is not the spinner but the indifferent International Cricket Council (ICC) which is at fault.
"There is no easy way to put this, no soft way to broach it, so here goes - Muttiah Muralitharan is throwing the ball," Richardson wrote in his column for Herald on Sunday.
"I know he's been tested, re-tested, tested again and cleared. And I know, with the special makeup of his limbs to the naked eye, his action looks worse than it is. But, for goodness sake, half of cricket is now not watched with the naked eye, thanks to the invention of super-slow-motion cameras, hot-spots, snicko and hawk-eyes.
"Many of the slow-motion replays I've seen of Murali have only strengthened my conviction he is exceeding the 15 degrees bending and straightening allowance. Is it not meant to be the other way round? Isn't the hi-tech equipment meant to alleviate my fears?" he asked.
Unlike former New Zealand captain Martin Crowe, who often flays Muralitharan, Richardson didn't blame the Lankan offie but opined ICC had failed to deal with the issue.
"I don't blame Murali for this situation. Murali can only do what he does -- and what he does he does as a champion, and unlike the other great spinner of my time, Murali does it with good grace and gentlemanly conduct," he said.
"The problem lies with the inappropriate way in which the ICC has decided to police throwing. A player is suspected of throwing and then, for want of a better term, tested in a laboratory. We've all seen the pictures of Murali lit up with bulbs. To his credit he volunteered for this. Apparently he proved he wasn't a chucker.
"But did he really? What he proved is that he can bowl within limitation, not that in the heat of battle he actually does," he said.
"Cricket is not played in a laboratory. On the field it matters where and how the ball gets to the other end. In a laboratory it doesn't, all that matters is how you delivered it," said Richardson, who represented New Zealand in 38 Tests and four ODIs between 2000-2004.
"Because of the way the ICC has gone about dealing with this situation, too many bowlers now appear to have suspect actions and can operate for too long before there is any reaction. Now is the time for the ICC to amend procedures to reflect how it is introducing technology," he added.