Three-month nickel on the London Metal Exchange rallied as much as 12.7% to $16,690 a tonne, its highest since April 2018. The contract eased later in the session to rise 6% by 0704 GMT.
The most-traded nickel contract on the Shanghai Futures Exchange rallied at its ceiling trading limit of 6% to 124,890 yuan ($17,733.00) a tonne, a record high.
"This is a very sexy price. For miners, higher price always makes us happy," said a trader with a nickel mine.
Traders and analysts cited market chatter that major nickel ore supplier Indonesia, which also supplies tin, could advance plans to ban export of ores.
Indonesia relaxed the ban in 2017, but said at the time that it would last only five years and that exports would be restricted again in 2022.
"People believe the ban is coming," said an executive at a major nickel producer in Indonesia.
London tin advanced 1.2% and Shanghai tin increased 0.8%, also having eased from stronger rallies in early Asian hours.
FUNDAMENTALS
* OPEN INTEREST: London nickel's open interest <MNI-OI-TOT> touched a record high earlier this month, while open interest for the Shanghai October contract hit its highest since March 2018, indicating strong interest in nickel.
* CHINA: China's exports unexpectedly returned to growth in July on improved global demand, despite escalating U.S. trade pressure, but the rebound may be short-lived as Washington prepares to slap even more tariffs on Chinese goods.
* CHINA COPPER: China's unwrought copper imports bounced back in July after two months of declines, jumping nearly 29% from June to the highest since January, while copper concentrate imports hit a record high, customs data showed.
* COPPER: Production at Chile's state-owned Codelco copper mining company fell 12.1% to 769,400 tonnes in the first half of 2019 compared with the same period last year, the country's Cochilco copper commission said on Wednesday.
* PRICES: London copper rose 0.9%, aluminium advanced 1.4%, zinc increased 0.4% and lead was up 1.4%. In Shanghai, copper advanced 0.9%, aluminium edged up 0.2% while zinc fell 1.4%.