The man was arrested on Tuesday night after police went public in the search for him.

Investigators have been told two primary school aged girls were at the park the corner of Macarthur and Little Clyde streets on Wednesday, 17 March when they were allegedly approached by an unknown male just before 5.45pm.

It's alleged the man asked the girls if they had seen his dog before assaulting them.

A 21-year-old man was arrested tonight and has been charged with two counts of sexual assault.

The Ballarat man has been remanded to appear in Ballarat Magistrates' Court on Wednesday.

EARLIER, TUESDAY 1PM: Footage has been released of a man police wish to speak to following an alleged assault of two primary school-aged children at a Soldiers Hill park.

Police are still looking looking for the man after the incident on Wednesday, March 17 at a park on the corner of Macarthur and Little Clyde streets about 5.45pm.

Detective Senior Constable Kellie Berry from Ballarat Sexual Offences and Child Abuse Investigation Team said police believed the incident was isolated and unrelated to any previous incidents, but could not confirm whether the man was local to the area.

Watch the footage here.

"Someone will know this man in this footage and I also just want to assure the public, in particular the local community, that it is an isolated incident and we do not believe that it is linked to any other reports," she said.

"The footage is pretty clear and we believe that someone will know this man. They know who he is and we need them to come forward as soon as they can and help us with our investigation.

Detective Senior Constable Berry said the incident occurred at a busy time of day and the girls and their families were receiving support.

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"It was approximately 5.45pm, lots of cars, people may potentially have some dash cam footage if they were in the area at the time," she said.

"These girls are prime examples of what you should do when something happens and went straight to a parent and they told them what happened and then we were called immediately."

Detectives from the Ballarat Sexual Offences and Child Abuse Investigation Team are appealing for public assistance following an incident at a Ballarat park earlier this month.

Investigators have been told two primary school aged girls were at the park the corner of Macarthur and Little Clyde streets on Wednesday, 17 March when they were approached by an unknown male just before 5.45pm.

Police have undertaken a significant canvass of the area as part of the investigation and have now located CCTV footage of a man they are looking to speak to in relation to the incident.

He is described as possibly being in his 20s or 30s, with short brown hair.

At the time of the incident he was wearing a grey and black hooded jumper.

Despite a number of enquiries, police have been unable to identify the man and are appealing for public assistance to try and locate him.

Alternatively, they are asking the man shown in the footage to come forward and contact police himself.

Police have not received any reports of similar occurrences in the Ballarat area and at this time it appears to be an isolated incident.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential crime report at www.crimestoppersvic.com.au