In a candid open letter to the financial markets minister dated March 21, SCA Chief Executive Jan Johansson said the authorities' relaxed stance on the rising crown would make it impossible to do business in the long term.

While the impact of the strong currency has spurred debate in local media and industrial lobbies in recent months, Johansson's remarks were the sharpest to date from major corporations more likely to stress their ability to cope.

"If the Swedish currency is allowed to become too strong, it will be impossible to run long-term and competitive industrial operations in this country," the boss of SCA, which makes hygiene and paper products.

Bolstered by some Europe's strongest public finances and relatively high interest rates, Sweden's currency earlier this month hit its highest level in trade-weighted terms since the crown's peg against the ecu, the forerunner of the euro, was abandoned in 1992.

Already struggling with a sharp fall in demand from the euro zone - the destination of around half of Swedish export goods - the country's exporters now face fierce currency headwinds.

But policymakers from both the centre-right government and the central bank have taken a relaxed view, saying companies need to adjust to the new currency landscape.

The crown has gained about 8 percent on the trade-weighted index since early June last year.

Johansson pointed to the cap on its currency introduced by Switzerland as an example of how other countries were seeking to safeguard their industries in the face of currency strength.

"Sweden is doing the opposite," he said.

"We cling to the view a strong crown is good for the country and testimony to sensible economic policy, while choosing to ignore how the export industry's competitive power is increasingly hollowed out," he said.

"In time, it will be devastating as investments dry up and industrial operations in this country become unprofitable."

(Reporting by Niklas Pollard and Christopher Jungstedt; Editing by Toby Chopra)