Commerce Secretary Algernon Yau on Tuesday said the SAR government still doesn't know whether new US tariffs on Chinese goods will also cover Hong Kong products, but in any case transit trade could be hit in the short term.

An additional 10 percent duty on Chinese exports to the US is expected to come into force on Tuesday, following the extra 10 percent imposed by US President Donald Trump last month.

Washington earlier clarified that the first tariffs move did apply to Hong Kong.

On a RTHK radio programme, Yau reiterated the government's opposition to Trump's decision.

"In fact, Hong Kong is a separate customs territory and the executive order is said to add duties on Chinese goods. But previous documents from the US Department of Homeland Security and the Customs and Border Protection have included Hong Kong goods as well. We have already announced that we'll file a complaint with the World Trade Organisation," he said.

"This time the US added another 10 percent levy on Chinese products. But it's very unclear; they did not say whether Hong Kong was included in the new tariffs. So we are studying whether they included Hong Kong this time."

Yau said transit trade could be affected, but the tariffs won't have a significant impact as Hong Kong's exports to the US account for less than 0.1 percent of the city's overall exports globally.

Separately, the commerce chief said there have been significant improvements in the city's trade of liquor, after tax on some spirits was reduced last October.

The duty on liquor with an alcohol content above 30 percent and with an import price of over HK$200 was cut from 100 percent to 10 percent for the portion above HK$200.

Yau said trading volumes of liquor increased by 60 percent from October to the end of January, while the value of the liquor traded rose by 150 percent.

"The momentum has been quite good in recent months. The reason we reduced the duties on premium liquor was that we wanted to develop Hong Kong into a trading centre for premium liquor. This would then have a knock-on effect to the catering, hospitality, logistics, and warehouse sectors, it could bring significant economic impacts," he said.

"We also hope to help Chinese baijiu to go global using the SAR as a trading centre. So we hope to boost trades on liquor, but not that we are encouraging people to consume more alcohol," he added.

Meanwhile, the minister encouraged SAR businesses to tap into opportunities brought by the rising e-commerce trend globally, noting that the sector accounts for some 20 percent of global trade, with revenues in this market rising by double digits on a yearly basis.

A second edition of the "Hong Kong Shopping Festival" will be held in the SAR in August to further capture the booming e-commerce business, Yau said, adding that authorities also hope to take the festival to Asean member states to promote Hong Kong products.