Child Youth and Family are disputing that Wairarapa social advocate Trevor MacKiewicz called their service with concerns about 2-year-old Caleb Skinner, three days before he was assaulted at his home.
Mr MacKiewicz told the Times-Age he called CYF on February 28 after he had noticed bruising and scratches on the boy's face.
On March 3 Caleb was airlifted to Starship hospital with severe head injuries. A man will appear in Masterton District Court on March 27 charged with assaulting Caleb.
Child Youth and Family co-ordinator Marion Heeney said they thoroughly searched their records and found no trace of Mr MacKiewicz's call.
"Based on the number given to us by Mr MacKiewicz we checked all calls to our national contact centre an hour either side of the time he told us he called.
"We also checked for calls starting with the same first five digits of the number provided by Mr MacKiewicz.
"In addition we checked all calls for the whole 24-hour period for 06 and unknown numbers. No trace of his call can be found."
The service asked for his phone records, which Mr MacKiewicz initially said he would supply. However, he has now said he is unable to provide them. He said he definitely made the call and believes the person he spoke to did not follow correct procedure.
"It's a departmental problem, not mine," Mr Mackiewicz said.
He said he is unable to supply phone records because the phone he used is not in his name.
"I've had the phone for 15 years, I just carried on paying their phone account. If I asked Telecom to do the search, they would not accept my authorisation."
Ministry of Social Development's Martyn Watterson said they want the public to call CYF if they feel a child or young person's safety is at risk.