Custody staff found the cash in Stacey Fernandez's underwear when they did a full body search of her in the cell and later found 9.7 grams of methamphetamine she had tried to flush down the toilet.

The 28-year-old pleaded guilty to drug trafficking, dealing with the proceeds of crime and committing an indictable offence on bail at the Ballarat Magistrates' Court on Thursday.

The court heard police intercepted the car Fernandez was a passenger in about 1.05am on April 16, 2021.

The police members did not find anything during a pat down search at the intercept scene but a custody officer found the cash in her underwear at the cells during a further search.

Staff who were cleaning her cell after she was transferred to another prison found the zip lock bag with methamphetamine in the toilet bowl under wads of toilet paper.

Police found messages about the sale of methamphetamine on her mobile phone.

Defence barrister Natasha Freijah said Fernandez's offending was at the lower end of seriousness because she was selling drugs to a small group of associates, not to the wider community.

She said Fernandez was selling drugs to fund her own drug habit and it was her first time charged with drug trafficking.

The court heard Fernandez would have the support of her family upon her release from prison and had completed treatment and programs in custody.

Her mother wrote to the court and said her daughter's time in prison had been a 'wake up call' and she had told her she was motivated to change.

Magistrate Ron Saines most people made the same comments when they were in prison, but the true test was their commitment to rehabilitation upon their release.

He said he rejected the defence submission that Fernandez should be released from prison on Thursday.

He said he was not satisfied someone who had been in and out of prison should not be released without supervision through a community corrections order.

"You have done pretty badly on community corrections orders in the past. If you go back to where you were you will be back to where you are now," Mr Sanes said.

"That is part of the reason for supervision.... to see whether you measure up to the personal change you say you have undertaken."

Fernandez will return to court later this month for sentencing.

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