VIENNA (Reuters) - The Swiss National Bank (SNB) may need to take its interest rates further into negative territory, its chairman Thomas Jordan said in an interview with the weekly NZZ am Sonntag.

FILE PHOTO: Swiss National Bank (SNB) Chairman Thomas Jordan attends a news conference in Bern, Switzerland December 13, 2018. REUTERS Denis Balibouse

Investors traditionally buy the Swiss franc as a safe haven, but the resulting increase in value against other currencies makes life hard for Swiss businesses. In July and August, the Swiss franc hit its highest level against the euro in two years.

With negative interest rates and increased foreign currency investments, the central bank tries to dampen demand for the franc and prevent the currency from becoming too strong.

In September, it left its main policy rate at -0.75%, one of the lowest rates in the world, and said it expects to stick to its ultra-loose monetary stance for the long haul.

“The phase of low interest rates could last even longer, and a further easing of monetary policy may also be necessary under certain circumstances,” Jordan told the paper in an interview to be published on Sunday, echoing recent comments from his deputy Martin Schlegel.

Asked whether the SNB’s shareholdings in U.S. companies, worth about 100 billion Swiss francs ($102 billion), could lead to friction with Washington, Jordan said the central bank was in close contact with the U.S. Treasury Department.

“Our interventions are never aimed at weakening the franc at the expense of other economies,” Jordan said.

He rejected the idea, raised by politicians, of making payments directly to individuals, so-called “helicopter money”, to strengthen their purchase power.

“(Such concepts) assume that the state can easily distribute money to the population via the central bank without leading to negative consequences in the longer term,” he said.

“It is a mixture of monetary and fiscal policy, which is playing with fire.”