A man busting to go to the toilet reached speeds of up to 176km/h on the Waikato Expressway.

Waikato police initially detected the vehicle travelling at 154km/h and then noticed it steadily increasing to 176km/h, Constable Will Hamilton posted on the Waikato Police District Facebook page this morning.

"Morning Team," he wrote. "Make sure you're well toileted before your trip. Apparently it's perfectly okay to do 176km/h in a 100km/h zone if you're busting to go to the toilet as one sergeant recently found out."

Hamilton told the Herald this morning that the sergeant was sitting at the Horotiu on-ramp doing paperwork with his radar on when he suddenly heard it "absolutely screeching".


"He looked up and saw the car was travelling at 154km/h and locked the speed in. He took off after the car and when he realised he wasn't making any ground he changed the [radar's] mode and locked it in again at 176km/h."

The officer chased the car, a rental driven by a foreign national, until it got stuck behind a truck at the 80km/h zone at the northern end of the city.

However, the car didn't pull over and only stopped at a red light at the intersection of Foreman Rd and Mangaharakeke Dr.

Despite saying he needed to go to the toilet, the driver also told the sergeant that he wasn't going to stop until he reached his friend in the CBD.

The driver was given a summons to appear in the Hamilton District Court on charges of driving at a dangerous speed and failing to stop.

Hamilton described the man's driving as "idiotic and mindless", especially as the busy festive period begins.

"If you crash - regardless of the cause or who is at fault - speed is the single factor that most affects the outcome. Just a few kilometres per hour can be the difference between avoiding a collision - or a crash with a tragic outcome."