Thirty-four-year-old Joanne Dahl, of Greystanes appeared in Wollongong Bail Court on Monday charged with possession and supply of a prohibited drug and also with possession of steroids.

A fact sheet tendered by police stated that Dahl was on bail for a similar offence when she was stopped for a breath test in Barrack Heights on Sunday.

While the result of the test was negative, police allege Dahl "was acting nervous and appeared anxious".

Following a record check, police believed she could have been in possession of illegal drugs or stolen items.

Dahl and two passengers were removed from the car, a white Toyota Hilux, while she and the vehicle was searched.

When asked if anything was inside the car, Dahl allegedly pointed to her brown handbag. When asked what was inside it, she allegedly said, "Drugs, because they are in my bag. I was just told to pick up something."

Dahl identified the drugs as "meth" and police found more in a plastic bag inside the car, as well as three small boxes of steroids.

According to the fact sheet the meth weighed 27 grams and had a street value of $10,000.

When searching Dahl, police also found a note hidden in her bra with writing on it "believed to be related to drug activity referring to drug weights and money".

Opposing bail at Monday's court hearing, police prosecutor Wendy Nolan said there was a strong possibility that, if found guilty, Dahl would be sent to jail.

There were also fears she would reoffend if granted bail.

Defence solicitor Kearney said that notwithstanding the current charges, Dahl had been complying in every respect with her previous bail conditions.

"I would like the court to take into account that she has no criminal history," Mr Kearney said.

Registrar Peter Ritchie said he was concerned that while on bail for a previous charge Dahl had attracted the attention of police in what was "a strong case".

Registrar Ritchie refused bail and sent Dahl down to appear before a magistrate on Tuesday.