Ukrainian exporters will have to sell half the foreign currency they earn to the government within a week under a new law signed Thursday by President Viktor Yanukovych.

The decree allows the National Bank of Ukraine (NBU) to introduce regulations obliging exporters to sell their foreign currency earnings no later than five days after contract execution.

The new rule, which will be a temporary measure valid for up to six months, is aimed at dealing with the current unstable external and internal currency market situation, according to the NBU.

The move will provide additional foreign exchange inflows of 1.6 to 2 billion dollars to the Ukrainian currency reserves, according to NBU analysts.

In the year to October, Ukraine's reserves have shrunk 8 percent to 29.255 billion U.S. dollars due to the country's rising public demand for foreign currency.

Ukraine abolished the mandatory sale of hard currency in 2005.