ASTANA, September 11 (RIA Novosti) - Kazakhstan's government announced on Thursday it will increase the customs duty on oil exports by 85% to $203.8 per metric ton on October 13.

Oil export duty has been at $109.9 per ton since May 17, based on an oil price of $714 per ton (around $97 per barrel).

The government said the move would ensure stable supplies to Kazakh oil refineries and yield over $1 billion in revenue to the national budget.

The oil-rich ex-Soviet republic last year produced 62.7 million tons (460.84 million bbl) of crude.