This should help bring down the global oil price, Reiche said, noting that fellow members of the International Energy Agency (IEA) were also struggling with rising prices.

"The International Energy Agency therefore asked its member states yesterday evening to release oil reserves amounting to 400 million barrels," Reiche said.

"We will comply with this request and make our contribution," she told a Berlin press conference.

Asked exactly which sorts of oil products would be released, Reiche could not say but said a total of 2.4 million tons would come out of the reserves.

Germany's current total reserves amount to about 19.5 million tons, economy ministry spokeswoman Susanne Ungrad said at a later regular press briefing.

Petrol stations in Germany would meanwhile be obliged to limit their price rises for petrol and diesel to one per day, Reiche said.

Past energy crises had shown that costs at the pump tended to rise rapidly with the oil price, but fall more slowly.

"We have therefore decided to limit the frequency of price changes," Reiche said. "Petrol stations are only allowed to increase their fuel prices once a day. But price reductions are allowed at any time."

The IEA requires its members to maintain oil reserves at all times that correspond to at least 90 days of their net imports.

Germany has so far tapped its strategic oil reserve three times, once during the Gulf War of 1990-1, after Hurricane Katrina hit US oil rigs in 2005 and then again in 2011 when the war in Libya disrupted oil exports.

While Germany's gas supply was secure thanks to Norwegian and US supplies, Reiche said, "the situation regarding oil supplies is tense" worldwide and impacting especially large Asian economies.

"The markets are clearly reacting with extreme sensitivity at present because no one knows how long the Strait of Hormuz will remain impassable, how long the war in the region will continue, or whether facilities will be hit," she said.

Oil prices surged more than five percent in early trading Wednesday and markets have see-sawed since the end of last month, when the United States and Israel attacked Iran, killed its supreme leader and plunged the Middle East into war.

Iran has vowed to close the Hormuz Strait, a vital sea lane, to shipping of countries it considers allied with the United States and Israel. The strait normally carries about 20 percent of the world's oil and gas supplies.