Arrivals of U.S. scrap copper into China last month stood at 5,236 tonnes, according to data released by the General Administration of Customs on Friday. That was up 14.3 percent from 4,580 tonnes in November, but was still less than one-tenth of the 60,440 tonnes imported in December 2017.

Shipments were 351,517 tonnes for the full year, down 34.3 percent from 535,371 tonnes in 2017.

Scrap material from key supplier the United States has been subject to a 25-percent import tariff in China since August as part of a tit-for-tat trade row, making imports much more expensive.

China's U.S. scrap copper purchases have since fallen sharply, with imports from Japan, up 49.2 percent year-on-year to 441,186 tonnes in 2018, partially filling the void. Japan was China's top supplier of scrap copper last year, the data showed, ahead of the United States and Hong Kong.

China has gradually been clamping down on broader waste metal imports for environmental reasons, with cargoes of Category 7 scrap copper such as coiled copper cable and waste motors completely off-limits from 2019.

Ahead of the ban, China's total scrap copper imports in December reached their highest in a year.

That jump came due to "the desire to preempt future controls", China scrap veteran Michael Lion, president of Lion Consulting Asia, said before the origin data was released.

"Albeit the trade and pricing outlook is not providing incentives to stockpile material," he added.

Meanwhile, imports of U.S. copper concentrate, also subject to a 25-percent tariff in China since August, fell 32 percent to 294,400 tonnes last year and were at zero in December. The United States was China's eighth-biggest copper concentrate supplier in 2017.

Shipments of U.S. scrap aluminium, which were hit with total Chinese tariffs of 50 percent last year, managed to hold up much better, falling by a relatively modest 16.9 percent to 513,850 tonnes in 2018. December imports were down 38 percent year-on-year at 39,923 tonnes.

(Reporting by Tom Daly; Editing by Joseph Radford)

By Tom Daly