Chinese steel and iron ore futures surged 4 percent to reach their upside limits on Monday as investors covered short positions on expectations prices may have hit bottom after sliding to record lows over the past two weeks. Steel and iron ore easily outperformed other commodities traded in China, sparking a flurry of physical deals on iron ore platform globalORE.

Helping brighten investor sentiment was data showing China's overall exports rose more than forecast and imports unexpectedly gained in September.

The most-traded rebar for January delivery on the Shanghai Futures Exchange rose as much as 4 percent to hit its exchange-set ceiling of 2,664 yuan ($435) a tonne, before paring gains to stand at 2,641 yuan by midday, up 3.1 percent.

On the Dalian Commodity Exchange, the January iron ore contract rose as much as 3.9 percent to touch its upside limit of 584 yuan a tonne. It was last up 3.4 percent a 581 yuan.

"It's short covering. I think generally the market is coming round to the idea that maybe we hit a short-term bottom and there are massive speculative short positions in both markets," said Graeme Train, analyst at Macquarie in Shanghai.

"I don't think the fundamentals would really justify a 4 percent leap in the day, so it's just a reflection of how short the market was."

Iron ore futures in Singapore also climbed. The November contract on the Singapore Exchange rose 3.1 percent to $82.87 a tonne.

The Chinese economy is also likely to reaccelerate in terms of activity after weakness in recent months, analyst Train said. China's exports rose 15.3 percent in September from a year earlier, beating forecasts in a Reuters poll for a rise of 11.8 percent. Imports rose 7 percent, defying expectations for a 2.7 percent fall and calming concerns about deteriorating domestic demand in the world's No. 2 economy.

China's iron ore imports rose 13 percent from August to 84.69 million tonnes in September, the second highest monthly volume on record, customs data showed.

The robust imports reflect continued strong supply from top exporter Australia, said Train, adding that some shipments for October may have been counted in September because of the Oct. 1-7 National Day holiday.

"Australia and Brazil's output should be stronger in the fourth quarter plus there's potential for a little bit of restocking on the mills' side that would keep demand reasonably elevated and keep imports rising for the rest of the quarter," he said.

Six Australian iron ore cargoes were sold on the globalORE platform in Singapore, five of which were 62-percent grade material sold at between $83.50 and $84.50 per tonne, according to the platform's website.

Those prices were up from deals done at just above $80 a tonne on Friday for the same grade, suggesting further upside potential for the benchmark price.

Benchmark 62-percent grade iron ore for immediate delivery to China .IO62-CNI=SI rose half a percent to $79.90 a tonne on Friday, according to data compiled by the Steel Index.

The price fell to $77.50 at the end of September, its weakest level in five years.

"I think the price can stabilise around $80 for a while, this is a price that looks acceptable for both suppliers and buyers," said an iron ore trader in China's eastern Shandong province.