Six people were injured in the three crashes, with one in serious condition in intensive care in Dunedin Hospital last night.
That 27-year-old man was the passenger in a car that crashed while being chased by a patrol car in Invercargill on Saturday.
Police said the Mazda MX coupe hit a centre island on Liddel St at 3.30am and crashed into a wall after a pursuit that lasted 90 seconds.
The 21-year-old driver of the car was treated at Southland Hospital and later released.
Police said a patrol turned on its warning lights after it spotted the driver allegedly crossing on to the wrong side of the road while turning a corner.
The driver appeared to be stopping, then took off and the patrol pursued.
Neither occupant of the car was wearing a seatbelt during the 2km pursuit, which reached speeds of up to 90kmh, police said.
On Friday, a 24-year-old motorcyclist received moderate chest injuries after he crashed into a ditch near Milton while allegedly trying to evade police, who say the pursuit reached speeds of up to 150kmh.
Police said a patrol signalled the motorcyclist to stop after there were reports from other drivers the motorcycle was overtaking dangerously.
The man, who did not have a motorcycle licence, did not stop and a short pursuit of about 1km ended when the motorcycle failed to take a moderate bend and crashed.
And on Thursday, a 31-year-old man needed hospital treatment for face and rib injuries after the van he was driving was crashed into by a teen driver allegedly fleeing police.
The teen also needed surgery for an arm injury and a female passenger required treatment for a suspected broken foot.
Police said an officer had pulled the teen driver over, but when he was found to be a suspended driver, he ran off, jumped in a car and drove off at high speed. Police had started to pursue the car when it crashed into the van about 200m along the road.
Southland police area commander Inspector Barry Taylor said the most recent incident, in Invercargill, was "yet another" example of a driver making a poor decision.
"This driver made the decision to not only place himself at risk, but also his passenger and other members of the public."
There was no fault on the part of police, he said.
"The information I have to date indicates the police officers concerned acted properly and were simply doing their job that is expected of them by the public at large."
Southern police district road policing manager Inspector Andrew Burns said it was a clear and simple choice for people to stop when requested to do so by police.
If a crash followed a pursuit it was the fault of those who decided to flee, he said.
