HARARE (Reuters) - Zimbabwe's treasury said on Tuesday the newly introduced gold-backed currency is the official unit of exchange for transactions and that it would soon introduce regulations to ensure businesses stick to the official rate.

Although it has remained stable on the official market since its launch early April, the Zimbabwe Gold (ZiG) has been off to a nervy start on the parallel market, with traders charging a premium of 65% to the official rate to obtain dollars.

Some supermarkets are also charging a premium above the market rate, which is set at ZiG 13.6 per U.S. dollar, for customers paying in the new currency while the ZiG is being rejected by informal traders.

"To ensure orderly pricing, Government will soon be introducing the necessary regulations to ensure that no exchange rate other than the official rate will be used for the pricing of all goods and services," Finance Minister Mthuli Ncube said in a statement.

The government has been making efforts to keep the ZiG afloat since its launch, with authorities launching a blitz on illegal foreign currency traders last month.

This is Zimbabwe's fourth attempt at having a local currency inside a decade, with the southern African country dumping the Zimdollar last month after it lost 70% value since the start of the year.

(Reporting by Nyasha Chingono; Editing by Sharon Singleton)