Paul Murphy has made a formal complaint to authorities over the leak to media about the impending prosecution of water protesters which emerged last night.
He said protesters - including himself - first learned they may be charged from the media.
Meanwhile, opposition TDs say they are "alarmed" about the DPP's decision to prosecute water charge protesters in connection with a demonstration targeting the Tánaiste last year.
It emerged last night that more than 20 protesters are set to be charged in connection with the Jobstown rally last year, which saw Joan Burton trapped in her car for over two hours.
The charges are expected to include false imprisonment and violent disorder.
Socialist TD Paul Murphy said he expects to be among those charged. He claims the potential charges amount to political policing - and has lodged complaints with the Office of the DPP, the Garda Commissioner, and GSOC.
“The first I and other protesters heard about this was on the Nine O’Clock news last night on RTE," he said in a statement.
"It is quite an incredible situation whereby the media is advised of charges in advance of those due to be charged. It also is in clear contradiction to the justification that was given for the huge numbers of Gardaí that were used to arrest all of the protesters – which is that we could have been potential flight risks.
"If we were flight risks, surely it would not make sense to leak this information to the media."
Murphy said the leak was designed to "spread fear amongst protesters" and that it could have only come from within the DPP or from gardaí, and he wanted to trace the source.
Now, Sinn Féin's Justice Spokesperson, Padraig Mac Lochlainn, said he is deeply concerned.
"Whoever the senior management are of An Garda Síochána who made the policing decisions need
to reflect: was it proportionate? Was it necessary, over ten days, to carry out raids?
"Could they not have brought these citizens in to the garda station in Tallaght? So yes, I think that it was disproportionate - and arguably, political policing."
It is thought that if the cases go to trial, the Tánaiste may be required to give evidence.