Japan's crude oil imports from Iran fell nearly a third in February from the same month a year earlier, trade ministry data showed on Friday, as tougher western sanctions targeting payments and insurance appeared to bite.

Imports by Japan, Iran's No.3 crude buyer, are expected to continue declining this year after dropping 39.5 per cent last year as the US and the European Union ratchet up sanctions targeting Iran's disputed nuclear programme.

Under pressure from sanctions, Iran's overall oil exports more than halved last year, costing it over $5 billion a month.

Japan's February crude imports from Iran were 953,848 kilolitres (214,268 barrels per day), down 32.3 per cent from a year ago and 19.1 per cent lower than in January, data from the Ministry of Economy, Trade and Industry (METI) showed.

For the first two months of 2013, Japan imported 2,132,205 kl (227,308 bpd) of Iranian crude, down 30.8 percent from the same period a year ago.

The figures contrast with customs-cleared data on Thursday which showed Japan's Iranian crude imports rose 15.9 per cent in February to the highest in eleven months, but the industry considers the trade ministry data a benchmark because it tracks the actual import status of oil tankers.

The International Energy Agency said in its March report that new US sanctions on Iran implemented in February, which barred the country from repatriating oil export earnings, appeared to have not had an impact on February shipments.

Iranian crude oil exports were expected to hold strong and even exceed 1.4 million bpd in March from 1.28 million bpd in February, said the IEA, which coordinates the energy policies of major consuming nations.

The report was at odds with industry expectations that the new U.S. measures would push Iran's exports in March to their lowest since Western sanctions came into effect in 2012.

Earlier this month, the United States extended 180-day waivers on Iranian sanctions to Japan and 10 European Union nations in exchange for their cutting purchases of the Opec nation's crude oil.

Most other major Asian buyers of Iranian crude also cut imports last month, although China, Iran's top crude oil customer, was an exception and imported 521,330 bpd, up 81 percent on the year.

India reduced oil imports from Iran by 43 percent to 259,000 bpd from a year ago, as New Delhi struggled with new insurance issues that may trigger more cutbacks in shipments from Iran.

South Korea imported 141,929 bpd from Iran in February, down 30 per cent on year, and its imports could plunge even further in March given a heavy refinery maintenance schedule.

The US in February imposed new sanctions against Iran, aiming to trap its oil revenues so they are locked up in a purchasing country and used solely for buying goods from that country.-Reuters