The spokesman for the Stuttgart state court said 33-year-old German businessman Marc Wiese was acquitted because of his "minor guilt" in the affair after he agreed to pay a fine.

"It was proposed to Marc Wiese that he be acquitted without judgement on the condition that he pay the sum of 10,000 euros (12,680 dollars)," said the spokesman, Reiner Skuyat.

Wiese was accused along with another Hamburg shipping firm executive of trying to help the main defendant in the trial, Hans-Werner Truppel, to ship 214 special aluminium tubes to North Korea via China.

Experts say the tubes, which were ordered by a Pyongyang diplomat, were to be used to build gas ultra-centrifuges in which uranium is enriched.

They were intercepted in April on a French freighter at the Egyptian port Damietta en route to North Korea.

Truppel, whose trial began in October, could face up to 15 years in prison for "furthering the production of a nuclear weapon" in violation of German export regulations.

The court spokesman said that Wiese had been called to testify when the court next sits on January 14.

Authorities quoted in German news magazine Der Spiegel said gas ultra-centrifuges built with the tubes could have produced about 10 kilograms (22 pounds) of enriched uranium within two years for a nuclear weapon.

North Korea said last year that it had produced enough weapons-grade plutonium for six atomic bombs by reprocessing spent fuel rods.

WAR.WIRE