Garda chief Martin Callinan has dismissed as "simply not true" allegations by a rank-and-file leader that some crimes are not being recorded while official figures are easily massaged.
After rejecting the remarks earlier, Mr Callinan again moved to maintain public confidence.
He said: "To reassure people, in cases where people are reporting crime they can rest assured they are recorded and investigated."
The Garda chief spoke directly with Mr Parker about the fall-out at the GRA annual conference, in Westport, Co Mayo. Mr Callinan said he had been reassured during the meeting that the grassroots Garda leader had no evidence of any wrong-doing over the reporting of official crime statistics.
Mr Parker had claimed officers were instructed over the past two years about new ways to classify offences.
Under the protocol, some crimes - including burglary - are being classed differently while others are going unrecorded because they are not backed up by statements, he said.
But Mr Callinan insisted: "That is simply not true."
The commissioner said he knew "for a fact" that all crimes are properly classified and investigated.
Amid the row, official figures released by the Central Statistics Office (CSO) showed robbery and burglary has soared since the economic collapse five years ago.