Police discovered more than a dozen bottles of steroid-related supplements when they raided the Sports Warehouse shopfront in the Crown Street Mall on December 4 last year.

Its proprietor, Figtree businessman Obadallah 'Obad' Homassey, also owns and runs sports supplement store Nutrition Boss, which has outlets in Shellharbour, Figtree and Miranda.

The chain is described as the "ultimate health food store" on the Stockland Shellharbour website, selling vitamins, herbal medicines, organic food and sports supplements.

Documents tendered to Wollongong Local Court this week said police investigating the supply of therapeutic goods in supplement stores received intelligence linking Homassey and Sports Warehouse to the unlicensed sale of restricted substances in the Illawarra.

Upon inspection, police located at least 17 bottles of steroids, stimulants and imported muscle recovery supplements hidden from public view behind the shop counter

Each bottle contained between 30 and 90 capsules and all were individually priced, the most expensive retailing at $199.95.

They had a combined retail value of almost $2,000.

Homassey was charged with possessing a prescribed restricted substance, possessing an androgenic steroid agent and possessing a prohibited substance under the Poisons and Therapeutic Goods Act.

The 60-year-old pleaded guilty to the offences on Tuesday.

Defence lawyer Patrick Schmidt told the court Homassey had run a successful nutrition business in Wollongong for 20 years and had never sold steroids to anyone in the past.

"If anyone comes in and asks for illegal steroids he shows them the door," Mr Schmidt said, telling the court Homassey had intended to use the supplements he'd been caught with as a tool for weight loss

"He made a complete and utter mistake in purchasing them. He will never be that careless again."

Magistrate Susan McGowan convicted Homassey and fined him $1,800.