Sweden is planning to test the impact of shorter working hours on productivity, in an experiment beginning on July 1. One group of government workers in the elderly care sector are to work six hours a day, while another will work the eight they are used to.

After a year, the municipal government will analyze the results and decide whether the six-hour day brings enough savings -- in the form of fewer sick days for instance -- that it warrants becoming permanent and extended to other sectors.

So far, the plan is limited to the civil service, but city councelman Mats Pilhem of the Left Party is convinced that all of Sweden is headed toward a shorter work day.

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"People have long work lives, and it's necessary to think of ways to create a more humane environment for them in the workplace," he said.

Critics like Malin Sahlen, an analyst at Timbro, a libertarian Stockholm-based think-tank, warn that the math does not add up in terms of the wider economy, saying it would be far too expensive to make a large part of the labor force work 25 percent less -- for the same pay.

"I think it's a crazy idea and I don't think it's going to be reality either," she said.

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Opponents say shorter workweeks have been experimented with across Europe -- 35 hours in France and Germany, an average of 30 hours in the Netherlands -- to mixed economic results.

"It's the kind of populist and socialist policy that's very dangerous for the economy, and we shouldn't go through with it," warned Maria Ryden, a member of Gothenburg city council for the center-right Moderates, which opposes the plans. "We're capable of working more."

But proponents of cutting the workday point at short-term benefits in the form of fewer sick days, and greater efficiency at work due to fewer breaks.

And they argue that greater savings will come in the long run, with a workforce that is less exhausted and therefore more productive as it approaches retirement.

Swedes may have even more time to relax if a six-hour workday is adopted nationwide.Getty Images

Pilhem says the concept has already proven its merits -- at Toyota.

Toyota's Gothenburg branch introduced the six-hour day in 2002 to make its facilities more efficient by having two shifts, one in the morning and one in the afternoon, instead of a single, longer one.

Robert Nilsson, a 25-year-old mechanic there, confirms that in his experience a six-hour day -- paid as much as eight -- is more efficient because it requires fewer breaks.

"Every time you have a break, it takes 10 to 15 minutes to get back to work, because you have to see where you were when you left off," he said.

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That efficiency is reflected in the salary, as the Toyota workshop pays technicians like Nilsson 29,700 Swedish kronor (3,300 euro, $4,510) a month, well above the 25,100 kronor (2,790 euro, $3,810) national average for workers in the private sector.

"It was a huge success straight away," said Toyota service center manager Elisabeth Jonsson.

"We saw the results, and everything was working for the staff, for the company, for the customers, so I don't think we ever had any discussion about putting an end to it."

"My friends hate me. Most of them think because I work six hours, I shouldn't be paid for eight," Nilsson said, talking while fitting part of a rear window onto a Toyota Prius with swift, expert moves.

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Sweden often stuns first-time visitors with its laid-back prosperity, making foreigners wonder how it is possible to have both lots of money and lots of leisure.

Part of the answer, according to economists, is a productive and well-educated workforce that adapts to new technologies quicker than most.

Exactly how much -- or how little -- Swedes work compared with other nations is a somewhat open question.

"We have a 40-hour work week, but also we have a little more absence than many people and we start work late in life because we study longer," said Sahlen.

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In 2012, the average Swede worked a total of 1,621 hours, according to the Paris-based Organisation for Economic Co-operation and Development.

This is more than the Netherlands with 1,381 hours, but less than Britain with 1,654 hours or the United States with 1,790 hours -- and way below Chile's 2,029 and Mexico's 2,226 hours.

"We could work more, that's a fact," said Sahlen.

But in an international productivity ranking by the Conference Board, a non-profit business research organisation, Sweden was already placed close to the top, coming 11th out of 61 countries.

The United States was third, the Netherlands number five, and Britain number 13, whereas Chile and Mexico were both in the bottom third.