Norwegian Prime Minister Jens Stoltenberg revealed Sunday that he has gone undercover as a taxi driver for an afternoon, in a bid to find out voters' real concerns.

"It's important for me to hear what people really think. If there's one place where people say what they think, it's in the taxi," he said in a video posted on Facebook, Twitter and YouTube.

The video was released while campaigning was in full swing for the September 9 general election, which Stoltenberg's ruling centre-left coalition appears likely to lose, according to the latest opinion polls.

Stoltenberg wore an Oslo Taxi uniform -- complete with a badge -- one afternoon in June and picked up passengers in a black Mercedes in the Norwegian capital.

A hidden camera fitted in the cab recorded reactions from the passengers, including one who remarked: "From this angle, you really look like the prime minister."

An elderly woman who also recognised Stoltenberg urged him to do something about the salaries of corporate bosses, complaining that "they should not make millions like that".

From the backseat of the cab, voters discussed issues ranging from education to oil policy.

Beyond revelations from the clients, Stoltenberg himself had one to give away, admitting to a passenger that he had not driven in eight years.

"I think it is going rather well," the young female passenger replied, adding: "At least I am alive."

Another female passenger was less impressed after Stoltenberg suddenly slammed on the brakes.

"This driving is not exactly the best I have seen," she said, laughing, adding: "I am not satisfied with this driving."

Asked by tabloid Verdens Gang if he would like to be a taxi driver if he lost the elections, Stoltenberg said: "I think that the country and Norwegian taxi passengers are better served if I were a prime minister and not a taxi driver."

According to the tabloid, the passengers did not have to pay for their journeys.

The Labour leader has steered the Norwegian economy -- buoyed by the country's oil wealth -- through the 2008 financial crisis virtually unscathed.

But his party, which took office in 2005, has seen support slide as it is viewed as having been in power for too long.

It has also faced harsh criticism for the authorities' lack of preparedness ahead of Anders Behring Breivik's Oslo bombing and island shooting rampage in 2011 that left 77 people dead.

An opinion poll published Monday showed the government garnering just 41 percent support, while the opposition Conservative party and its three allies had almost 53 percent of voter sympathies.

Stoltenberg did however win over at least one voter with his cruise around town.

While alighting from the taxi, an elderly male passenger told him: "This has been nice... I will vote Labour Party."