A police spokeswoman said they were called to a report of a stolen vehicle and a person allegedly assaulted on George St about 6.15am today.
One person was taken to Dunedin Hospital with serious injuries and the stolen vehicle was later found in Mosgiel.
"Police are making inquiries to determine the circumstance of the incident and to locate the alleged offenders," she said.
Armed police and about seven police vehicles were seen in Milton on State Highway 1, near Duthie St, about 10am.
The armed offenders squad was also called to the scene. Two members of the dog squad also attended.
The spokeswoman later confirmed that the incidents were related and another vehicle was located in Milton.
Four people were arrested, she said.
The ODT understands the incidents are meth and gang related.
