Sergeant Maurice McCabe is still being victimised and isolated by senior members of the force, according to the chairman of the Public Accounts Committee (PAC).
John McGuinness also said gardaí needed to urgently change their attitude towards whistleblowers.
The PAC has published its long-awaited report on the penalty points issue, saying the Gardaí should report every year on the number of penalty points being quashed.
Mr McGuinness said Maurice McCabe's contribution to the State still is not being valued by senior Gardaí.
"What he has done in the interests of the Gardaí and the State is not fully appreciated," he said.
"He is still isolated (and) looked upon by the senior members of the Force as someone who stood out from the Force and perhaps should not have done what he did."