Tehran: Iran has received less than a third of the USD 4.8 billion India owes it in oil arrears because of payments problems, the Managing Director of the National Iranian Oil Company said on Monday.

"Up until last week, India owed us USD 4.8 billion dollars, but during that week we received 1 billion Euros (USD 1.4 billion)," the Deputy Oil Minister Qalebani said.

"Oil sales to this country (India) are more or less continuing according to earlier plans," he added.

Indian firms have been struggling for more than six months to pay Tehran because of international sanctions imposed over Iran's controversial nuclear programme. The sanctions include banking restrictions.

The payments problem arose when various Asian and European banking channels used by New Delhi to pay Iran -- Germany in particular -- were closed off one after another.

On July 31, Qalebani said the payment problem had been solved, confirming remarks by Indian Petroleum Minister S Jaipal Reddy who had said his country would use a banking system via Turkey to pay for Iranian crude.

India is Iran's second largest client after China, and absorbs about 20 per cent of the Islamic republic's crude exports, buying about 400,000 barrels of Iranian crude per day.

Annual trade between the two nations stands at an estimated USD 12 billion.