Video has emerged of a mounted police officer grabbing a woman by the hair before she falls to the ground during a dramatic confrontation on Hindley St during New Yearís Eve celebrations in the city overnight.

Footage shows the woman arguing with another person next to the mounted officer.

The woman appears to try to punch the other person under the horseís head. The police officer grabs her and she falls to the ground.

She is restrained but itís not clear if she is arrested. A SAPOL spokesperson said they had no information on the matter.

It was one of several incidents overnight as revellers farewelled 2018.

A police officer was injured in a hit-run at Mile End while more than 100 people were arrested.

Despite a slight increase in the number of arrests compared to last year, police are pleased with crowd behaviour across the state.

Some incidents of note included one man who was arrested and two others fined for behavioural offences at the Big Bash cricket at Adelaide Oval.

In a separate incident, a police officer was hit by a Mazda sedan at a road breath testing station on Henley Beach Rd, Mile End, just before 1am.

The sedan drove off while the male officer suffered minor leg injuries.

He was taken to hospital but has since been released.

Major Crash detectives are investigating the collision and following positive lines of inquiry with the carís registered owner.

Police are appealing for the driver and any witnesses to come forward.

Between 7.30pm on New Yearís Eve and 7am the following day, there were:

- 109 arrests

- 16 reports

- 117 general expiation notices

- 45 out of 5937 people tested positive to alcohol while driving

- 21 out of 345 drug driving tests returned positive

The highest breath test results recorded was from a 20-year-old motorcyclist, who returned a blood alcohol reading of 0.186 about 6pm at Port Lincoln.

How SA celebrated NYE
The male rider also never held a licence, was currently disqualified from driving and the motorcycle was unregistered and uninsured.

At the Glenelg and city declared public precinct, there were:

- 41 people ordered to leave

- one barred from the city DPP

- three minors removed from Glenelg DPP

- two arrests and six fined at Glenelg DPP

Police warned alcohol and other substances can stay in the bodyís system for a long time and they would be conducting random driver testing on New Yearís Day.