Dannika Slater-Parsons, 22, of North Wallacedale Road, pleaded guilty in Warrnambool Magistrates Court to theft and assaulting an emergency worker on duty.

She is believed to be the first person in the south-west to be handed the mandatory six-month jail term after the new law was introduced in September last year.

Those who attack and injure emergency workers on duty are no longer able to be sentenced to a community corrections order or any other non-custodial outcome, even after determining that special reasons apply and that the statutory minimum sentence should not be imposed.

Magistrate Mark Stratmann said emergency services workers should not be subjected to violent assaults while doing an important job for the community.

"This is serious offending," he said.

"The new legislation clearly reflects that view."

On July 26 last year Slater-Parsons was in custody at the Hamilton police cells when she headbutted a female police custody officer to the forehead about 11am.

The court heard the victim suffered a mild concussion and was advised by a medical practitioner to take two days off work.

At the time of the offending Slater-Parsons was in custody for a number of thefts at FoodWorks supermarket in Casterton's Henty Street, as well as the theft of clothes from an opportunity shop in Hamilton's Cox Street.

Mr Stratmann said he had considered Slater-Parsons' age and personal circumstances - including her good prospects of rehabilitation and available support services - and would not exceed the six month mandatory jail sentence.

He said Slater-Parsons had accumulated 11 pages of criminal history in less than 12 months.

"It is a lot of criminal offending in the space of a very short time," he said.

"You committed a lot of thefts in a small supermarket, in a very small town with just under 3000 people.

"Everyone knows everyone and everyone knows who runs the supermarket. You make those people feel scared and un-trusting. That affects everyone else in the community."

Slater-Parsons has already served 139 days in custody on remand and is expected to be released in late August.

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