An unidentified middleman with a company registered in Hong Kong has been authorised by the North Korean government to select a Hong Kong-based architect to redesign the secretive country's airports. Local urban planner Otto Cheng Ping-lun, of PLT Planning and Architecture, told the South China Morning Post his proposal to redesign the military airport at Kamgang Tourism Zone, Wonsan, into one for civilian use had impressed state leader Kim Jong-un so much that North Korean authorities invited him to bid for the redesign of Pyongyang's airport as well. "We were told that Kim was happy with our design. However, Kim said the airport in the capital should not look worse than the one in the economic zone. That's why we were also asked to upgrade the airport in Pyongyang," Cheng said. Cheng said the exterior of the airport at Mount Kamgang - a scenic tourism area in the southeast of the country - resembled the drum used by dancers in traditional Korean musical performances. "We were approached by a potential investor who is very close to the North Korean government," he said. Cheng said the investor, whose company is registered in Hong Kong, was authorised by North Korea to choose an architect to design the Pyongyang airport. He declined to reveal further details of the investor, including whether he was a mainlander. "My partner was invited [to fly to North Korea] on a private jet provided by the investor. Of course, they had to leave their mobile phones in the airport before entering the country," he added. In contrast to Hong Kong's International Airport, which receives over 55 million passengers a year, the US$200 million project in Kamgang can only accommodate 12 planes and would receive 1.2 million tourists annually. The project requires lengthening the runway from 2,450 metres to 3,500 metres. Cheng said construction was on hold after the missile tests conducted by Kim earlier this year, but he was optimistic that the project would go ahead. "We believe [Kim Jong-un] will turn his attention to the economic front soon," he said. News of Cheng's firm being invited to redesign the military airport was first revealed last month by North Korea News, an independent website based in Washington and Seoul. North Korea's consulate in Hong Kong did not reply to the Post 's inquiries regarding the airport plans. Cheng started his career in the early 1990s and worked for major planning firms in Hong Kong. He was involved in drafting the city's Metro Plan for urban areas in the 1990s and designing Tung Chung new town. But he said local projects were now less satisfying as the city was less receptive to creative ideas. The airport is not the first unusual project awarded to Cheng's firm, which is run by 30 staff in two offices in Hong Kong and Shanghai. Most of his projects have two things in common - they are very large in scale, and involve clients from non-Western countries, such as Iraq, Peru, Russia and the mainland. Some are linked to the families of state leaders, like North Korea. Cheng admits there is a downside to working with such clients. "We didn't get paid for a new town design of 6,000 hectares when the government of Kyrgyzstan was overthrown," he said. PLT Planning is now designing a new town of 24 sq km for the government of Abu Dhabi, eight times the size of the new towns planned in the New Territories. The firm's British partner, Sheppard Robson, was noted for designing the UK's first zero carbon house in 2007.