Controversial radio talkback host Ray Hadley has broken down while discussing the arrest of his police officer son on possession of drugs.

Hadley’s son, Senior Constable Daniel Hadley, was on Friday arrested at a pub at Rouse Hill, in Sydney’s north-west, after an investigation by the Professional Standards Command, with 0.79 grams of cocaine worth about $200.

In a press conference on Saturday, an emotional Hadley senior fought back tears as he said he was “angry and perplexed” when he was first told of his 28-year-old son’s arrest.

“I brought Daniel back home and my anger turned to shock and sadness,” the 2GB shock jock said.

“I had no idea my son, a respected police officer, would be involved in such a matter.”

Ray Hadley with son Daniel when he graduated from police college. Photo: Twitter

He said Daniel, his eldest child, had later revealed he’d been battling a mental health condition for some time.

“The serious nature of the illness is such that he’s been admitted already today to a clinic to deal with it,” Hadley said.

“‘He is not in control of his mental health. It is a very serious problem.”

Later in the packed press conference, the talkback host broke down as he admitted he’d felt “particularly inadequate as a father and as a spokesman for [national mental health campaign] RU OK day”.

“I now know how many parents feel when they think things are okay but they’re not,” he said.

”I love him dearly. I wish to God he’d come to me before this.”

Watch Ray Hadley’s emotional press conference

Hadley explained that Daniel had dislocated his knee while on duty some time ago and that his seven years as a police officer had “had a dramatic impact on him”.

Daniel was granted bail and is due to appear in court in September.

Soon after his arrest, another man was caught nearby and charged with supply and possession of a prohibited drug and goods in custody.

“I feel particularly inadequate as a father”: Ray Hadley. Photo: AAP