Norwegian media reported that some of the people in a video of Prime Minister Jens Stoltenberg posing as a taxi driver were paid for taking part.
Norway’s ruling Labour Party confirmed that 5 of 14 passengers filmed in the cab had each been paid 500 kroner ($85; 64 euros).
But while they had been asked to take part in a Labour video, they were not told what it involved, it said.
Jens Stoltenberg said he wanted to hear from real voters before polls next month.
The prime minister’s party, in power since 2005, is trailing Norway’s Conservative Party in opinion polls.
The video, made in collaboration with an advertising company in June, is due to be screened during the election campaign but has already been posted on Jens Stoltenberg’s Facebook page.
News that five of Jens Stoltenberg’s passengers were not picked up at random was revealed by Norway’s Verdens Gang (VG) tabloid.
“They’re five ordinary people who were asked if they wanted to take part in a video for the Labour Party and who knew nothing else, except that they were going to be picked up in a taxi,” party spokeswoman Pia Gulbrandsen said.
“Their spontaneity was real when they realized that the driver was the prime minister.”
None of the passengers had to pay for their ride.
Jens Stoltenberg came in for criticism for his driving, at one point jolting the car abruptly when, he said, he had mistakenly applied the brake pedal on the automatic car, thinking it was the clutch.
The two-term prime minister said he had not driven in eight years.