Footage of a small car undercutting a lorry, near the Moira roundabout, posted on social media has gone viral on social media.
The post on Idiot drivers Northern Ireland has been viewed 119,000 times, shared 644 times and received 955 reactions.
The Facebook post explains the footage was taken "On way to Moira from Nutts corner".
When asked for a comment on the footage, Sergeant McKendry said he was "horrified by the driver’s actions".
"We are appealing for anyone who was driving in the area and saw this car to get in touch using the telephone number 101. Information can also be given anonymously via the independent charity Crimestoppers on 0800 555 111."
He added: "Driving on public roads brings with it certain responsibilities for drivers and passengers; for their families and friends and to the community as a whole.
"These responsibilities should not be taken lightly. It is important to point out that drivers should expect to receive a fine or worse, prosecution through the courts, should they be detected engaging in careless or dangerous driving, or modifying their vehicle illegally.
"Our message is bad driving standards will not be tolerated.
"They need to realise if they are taken to court, their licences may be at risk and the loss of a licence could impact on their entire futures. We want these drivers to realise the dangers they are causing to themselves and other road users.
"The last thing police want is to be knocking on doors of relatives following a fatal crash caused by someone showing off in a car."