THE US Treasury Department has forbidden US citizens to do business with 20 Hong Kong shipping companies, which formed the bulk of 26 on the global banned list, for failing to uphold UN sanctions against Iran over its refusal to stop nuclear development.

In response, the Hong Kong government said it "will make the relevant subsidiary legislation to designate entities subject to financial sanctions as decided by UNSC [UN Security Council]", adding that it would "continue to exercise vigilance in enforcing our local legislation to effectively implement the UNSC sanctions against Iran."

Among those 26 firms, 24 are accused of doing business with state-owned Islamic Republic of Iran Shipping Lines (IRISL), or its front companies. Two companies are affiliated with Aerospace Industries Organisation (AIO), a subsidiary of Iran's defence ministry, said the Treasury Department statement.

Twenty companies linked to IRISL are based in Hong Kong with another four operating from the Isle of Man, a self-governing British territory. The two AIO affiliates are Tehran-based.

IRISL started to change the registration of its vessels in the summer of 2008, which include 20 ships in Hong Kong and others in Germany and Malta, reported the South China Morning Post.

Meanwhile, IRISL changed ownership of its 20 Hong Kong-flagged to companies registered in Hong Kong, including Starry Shine International Ltd, Ideal Success Investments Ltd, Top Glacier Co Ltd, and Top Prestige Co Ltd, four of which are backlisted.