German Foreign Minister Guido Westerwelle ruled out military intervention in Iran once and for all, saying as he arrived for talks in Brussels: "We are not taking part in the discussion on military intervention."
"We believe such discussions are counter-productive and reject them."
But Britain said all options should remain on the table.
Asked to comment on talk of a strike against Iran, Foreign Secretary William Hague said: "We are not considering that at the moment. We are not calling for or advocating military action.
"At the same time we say all options should remain on the table.
"Of course we will also look over the coming months to increase the peaceful legitimate pressure on Iran as part of our dual-track approach of being available for negotiations if they're real negotiations, but at the same time placing more pressure on Iran through sanctions."
The 27 ministers will discuss "strong new restrictive measures" against Iran failing progress in Tehran's cooperation with the UN nuclear watchdog, the IAEA, or in its stalled talks with world powers, diplomats told AFP.
Tension between Tehran and its two principal foes, Israel and the United States, has risen since an IAEA report last week said there was "credible" evidence suggesting Iran's atomic programme was being used to research putting nuclear warheads in ballistic missiles.
French Foreign Minister Alain Juppe said the international community needed to take "a very firm" stand by toughening sanctions against Iran "to avoid an irreparable intervention".
Diplomats said a draft statement to be mulled by the ministers states that "Iran is in violation of international regulations".
It goes on to say: "We urge Iran to address international concerns ... Strong new restrictiive measures will be taken at a next meeting taking into account Iran's actions."
Swedish Foreign Minister Carl Bildt also opposed military action, saying "some hype" was built around the report by the International Atomic Energy Agency.
"I don't think any military response is justified or called for. We have to solve this by diplomatic means," Bildt said.
EU foreign policy chief Catherine Ashton is representing six world powers -- Britain, China, France, Germany, Russia and the United States -- in stalled talks with Iran aimed at convincing Tehran to freeze nuclear activities.