China supplies about 95% of the bloc's demand for magnesium, a key ingredient in aluminium and steel, but shipments have dried up since September, a statement said.
"Without urgent action by the European Union, this issue, if not resolved, threatens thousands of businesses across Europe, their entire supply chains and the millions of jobs that rely on them," said the joint statement by a dozen industry groups, including metal producers, auto suppliers and the packaging sector.
Europe is expected to run out of magnesium stocks by the end of November, they added.
The Chinese government's efforts to curb power consumption have hit output of a range of metals, including magnesium, also widely used in the aerospace industry.
Prices of magnesium in China have soared, more than doubling over the past year to $4,700 per tonne, the highest since 2008.
In Europe, remaining stocks are going for $10,000-$14,000 a tonne, the statement said.
"The magnesium supply shortage should be discussed in the same international fora as the semiconductors shortage," Eurometaux, the European Association of Metals, told Reuters in a separate email.
In the longer term, Europe should examine whether it can restart domestic magnesium production after the sector closed in the early 2000s due to low Chinese prices, Eurometaux added.
(Reporting by Eric Onstad; Editing by Kirsten Donovan)
By Eric Onstad
