Oman is set to impose a new tax on liquor and cigarettes starting June following a royal decree issued on Wednesday by Sultan Qaboos bin Said.

The introduced "sin tax" will tariff 100 per cent on tobacco, alcohol, pork and energy drinks, and 50 per cent on carbonated drinks.

The sin tax, also known as excise tax, applies to goods that are deemed harmful to public health and the environment.

Oman is following in the footsteps of Saudi Arabia, UAE, Qatar and Bahrain as part of a 2016 tax agreement by the six-nation Gulf Co-operation Council.