The car was travelling north in the southbound lane of Waihi Rd, heading into oncoming traffic.
Wannop said the car seemed to slow and "hesitate" but eventually continued in the wrong lane.
In the video, a sedan indicates left as it crosses the Takitimu Dr overbridge but a traffic island separates the two directions.
At the intersection of Waihi Rd and the Takitimu Dr exit ramp, the car uses a southbound merger lane to cross over into the northbound lane and continue towards Eleventh Ave.
Wannop said they last saw the car turning on to Cameron Rd.
He posted the 20-second video to a Tauranga community Facebook page where it garnered a lot of attention.
"It's gone viral," he said.
Wannop said he reported the incident to police yesterday.Police said this afternoon they were aware of the video.
A spokeswoman said they encouraged anyone who witnessed an incident like this to note details of the vehicle, including the registration, and phone police at the time so they can follow up.
Meanwhile, an Auckland truck driver said he witnessed the worst piece of driving in his life as a car overtook him on winding yellow lines in a gorge near Rotorua this month.
The man, who did not want to be named, was taking his parents, on holiday from India, from Tauranga to Rotorua when his father videoed the vehicle.
The video shows the man negotiating a winding section of State Highway 36 when he is suddenly overtaken by a white four-wheel drive.
The vehicle passes them on a blind corner on the yellow lines before carrying on in the distance, cutting the corner while approaching the next turn.
"I was just shocked because I was driving to Rotorua with my family and we were just going around a corner and the car just came out of nowhere," the man said.
"The gorge from Tauranga to Rotorua is really dangerous, especially in that portion. You can't drive like that."
Going by the look of the vehicle he doubted it would be tourists behind the wheel.
He said they continued to see the car in the distance for a short period which showed the driver continuing to cut the corners.
"He just didn't go over [yellow lines] once, he was doing it over and over."
He said the incident occurred on March 15 about 5pm.
He shared the video because he had been monitoring the road toll in the media and said driving like this did not help keep people safe.
"The death toll on our roads is spiking, so that's really terrible. Just imagine if a car just came out in front of it, what would happen? An accident."
The 27-year-old labelled the driving the worst he had ever seen.
"I'm used to watching this, but that was just terrible ... one of the worst, I think worst."
The police have been approached for comment about the incident in the gorge.