A man who parked his car temporarily at the entrance to the Parliament building here to take a security pass had a tense moment when his car rolled back into the official car of Prime Minister Datuk Seri Najib Tun Razak, Wednesday morning.

Kuala Lumpur police chief Datuk Mohmad Salleh said the man, in his 20s, was said to have forgotten to engage the hand brake of his Volvo car resulting in the car rolling back and knocking into Najib's Proton Perdana at 9.50am.

"The Prime Minister was unhurt in the incident. Najib was on his way to Parliament," he told reporters at city police headquarters.

He added that Najib's car also did not sustain any damage in the incident.

Mohmad said investigations did not reveal any criminal intention in the incident which was investigated under the Road Transport Act 1987.