North Korea has been smuggling banned materials which could be used for rocket and missile launches, often using forged documents to disguise their destination, local media reported Thursday.

South Korea has secured evidence that materials related to the weapons of mass destruction were exported to the North through China and other countries, Munhwa Ilbo newspaper reported, quoting unnamed government officials.

"North Korea has smuggled commodities related to weapons of mass destruction banned by the international community and luxury goods through detour routes such as China, Japan, Mongolia and Russia," it said.

Illegal methods used by the cash-strapped communist country to evade sanctions have become more creative than before, the newspaper said.

South Korean officials refused to confirm the report.

UN resolutions adopted after the North's missile and nuclear tests last year ban transactions linked to its nuclear and atomic activities and the supply of luxury goods to Pyongyang.

The United States has announced new sanctions on the North to punish it for the sinking of a South Korean warship in March with the loss of 46 lives, and to push it to scrap its nuclear weapons programme.

Seoul found that a Chinese company had fabricated documents to export measuring equipment to the North in April, Munhwa Ilbo said, adding such equipment could be used for long-range rocket or missile launches.

The South's Yonhap news agency carried a similar report and said Seoul and Washington have been watching closely as the North used US measuring equipment to launch a long-range rocket last year.

South Korean officials believe the measuring equipment smuggled this year could be used to launch missiles, it said.

Munwha Ilbo added that two Japanese traders were caught by police in June attempting to export second-hand digging equipment, which could be used as a missile launch pad, to North Korea.

South Korea has collected information about North Korean officials using diplomatic pouches to smuggle whisky, cigars and drugs, the newspaper said.

Pyongyang now favours Mongolia and Russia to smuggle banned goods because of tightened regulations in China, it said.