Thursday's arrival could have come from Hong Kong or China, several traders said.

Traders saw copper inflows from South Korea late last week but said they had not seen arrivals of Korean shipments this week.

"We are still checking where yesterday's copper was from. Most likely it's from Hong Kong or China," said one trader at a local metals company.

The trader, however, said the rise was still "acceptable" so far and that more copper could arrive at Singapore warehouses if low domestic prices in China failed to pick up.

A senior trader at a European trading house also said the metal probably came from Hong Kong or China.

"There is still market talk of more Chinese copper coming here," said the trader.

Traders say copper cargoes in Hong Kong, originally designated for China, were ready to come to Singapore as it hadbecome increasingly difficult to ship the metal into China.

In a bid to help its copper industry, China cut export taxes earlier this year and increased crackdowns against smuggling of the metal in recent months.

Copper premiums, however, were little changed at under $20 with few offers and inquiries.

Apart from copper, traders saw little movement in other base metals in Southeast Asia.

One trader said he had not seen Chinese zinc heading to Singapore, through which the metal goes to Southeast Asian countries.

"It's been quiet for a while, but Chinese zinc may come again later this year. After all Singapore is the main destination," said the trader.