The prosecution is expected to call 30 witnesses, including a firearms expert, in the case against shipping firm APL and its container ship captain Pan Xuejun, who have both been charged with transporting nine Singapore Armed Forces (SAF) armoured vehicles to Hong Kong without a licence.

Yesterday, defence lawyers sought an explanation from the prosecution on why the two defendants, who were initially charged separately, now face a joint charge.

The combined charge states that APL and Pan allegedly imported nine vehicles designed or modified for military use under a sea waybill, without an import licence issued by the director-general of trade and industry.

District judge Anthony Kwok Kai On asked the prosecution to provide an explanation for the combined charge and adjourned the case to July 25.

In a joint charge, both parties would be equally liable for the alleged offence. The offence carries an unlimited fine and up to seven years' jail.

According to Hong Kong's Customs authorities, all vessels must fully declare all cargo on board before docking at its port. Generally, cargo in transit does not require an "import or export licence".

But such a licence is required for certain types of strategic commodities.

Pan, 39, a Chinese national, was the captain of an APL vessel which was transporting the Singapore-made Terrex infantry carriers back to Singapore after a military exercise in Taiwan last year.

The ship stopped in Hong Kong on Nov 23 without an import licence issued by the city's director-general of trade and industry. This led Customs officials to seize the Terrex vehicles. The vehicles were later returned to the Republic and arrived in Singapore on Jan 30 this year.