A 29-year-old Hamilton man was travelling north on Tuesday afternoon when he overtook another car.

Leading Senior Constable David Rook said the man's Holden aqua-planed in heavy rain and went into a tree.

The man was the sole occupant in the vehicle.

"He was unhurt thanks to his seatbelt," Leading Senior Constable Rook said.

"The tree is on the passenger seat."

He said alcohol, drugs and speed were not factors in the incident.

"It just shows the importance of wearing a seatbelt that he was able to walk away from this," he said.