Prime Minister Malcolm Turnbull's nephew has reportedly been charged with cocaine possession.

Harry Hughes, a former staffer for NSW Planning Minister Anthony Roberts, was arrested at a bar in Sydney's CBD last month, according to The Australian.

Mr Hughes was said to be caught by undercover detectives, who allegedly found 0.7g of cocaine in his possession.

'About 5pm on Friday 6 July 2018, officers from Redfern Region Enforcement Squad stopped and searched a 23-year-old man on Phillip Street, Sydney, before seizing an amount of cocaine,' the statement read.

'The man was arrested and charged with possess prohibited drug.'

Police said the man appeared in Sydney's Downing Centre Court on July 30 where he was granted conditional bail. He will next face the same court on September 10.

Mr Hughes was moved on from job as Mr Roberts' staffer last September, reportedly at the request of Premier Gladys Berejiklian, who wanted the planning minister to have fewer political advisers and more planning aides.

He became a lobbyist for property developers within a month and registered Axis Strategic Advisory, which lists clients including Atilol Holdings, The Sydney Morning Herald reported.

Daily Mail Australia has contacted the Prime Minister's office for comment.

The allegations come after Ray Hadley's police officer son was arrested and charged with cocaine possession on Friday night.

Senior Constable Daniel Hadley was allegedly caught with of 0.79 grams of the drug, with a street value of $200, at the Australian Hotel and Brewery at Rouse Hill in Sydney's north-west.

He was admitted to a mental health clinic after being granted bail at the weekend following an internal police investigation.

Police are reviewing Daniel Hadley's employment and removed him from 'operational duties'.

Ray Hadley fought back tears in an emotional press conference following his son's arrest, saying he felt 'inadequate as a father'.

Daniel Hadley is expected to face Parramatta Local Court on September 12.