It's Saturday in Bhutan and Lotay Tshering has just completed urinary bladder repair surgery on a patient at the Jigme Dorji Wangchuck National Referral Hospital.

But Tshering is no ordinary doctor. During the week, he also happens to be the prime minister in the Himalayan kingdom famous for measuring citizens' Gross National Happiness.

"For me it's a de-stresser," said Tshering, who was elected prime minister of the nation of 750,000 people last year in only its third democratic election since the end of absolute monarchy in 2008.

"Some people play golf, some do archery, and I like to operate. I am just spending my weekends here," the 50-year-old said.

At the hospital, Tshering's patient, a 40-year-old man named Bumthap who underwent a five-hour bladder repair surgery, told AFP he was pleased with the results.

"Now that I have been operated on by the prime minister, who is considered one of the best doctors in the country, I feel more relieved," he said.

No one at the hospital bats an eyelid as Tshering, wearing a faded lab coat and crocs, walks through the busy corridors. Nurses and hospital attendants continue with their jobs as normal.

The Buddhist kingdom is in many ways a case apart, benchmarking itself on happiness instead of economic growth.

The capital Thimphu has no traffic lights, the sale of tobacco is banned, and television was only allowed in 1999.

But the "Land of the Thunder Dragon" also has its problems, among them corruption, rural poverty, youth unemployment and criminal gangs.

Tshering, who trained in Bangladesh, Japan, Australia and the United States, began his political career in 2013, but his party failed to make headway in that year's election.

After losing, King Jigme Khesar Namgyel Wangchuck commanded him to lead a team of doctors and travel with the monarch's entourage to far-flung villages to provide free medical treatment.

Now as prime minister, he spends Saturdays treating patients referred to him and Thursday mornings offering medical advice to trainees and doctors. Sunday is family time.

"I will continue doing this until I die and I miss not being able to be here every day," he added.

And on the days when he drives his car around the capital Thimphu -- instead of using his official chauffeur -- an-all-too familiar urge takes hold of him.

"Whenever I drive to work on weekdays, I wish I could turn left towards the hospital."