Danish Prime Minister Helle Thorning-Schmidt has told euronews she wants to see a full ban on Iranian oil into Europe by July.
The EU has, in principle, already agreed to an embargo against Tehran as part of a package of sanctions to disrupt its disputed nuclear programme.
Details on how to halt Iranian crude imports into the EU, however, still need to be worked out.
“I hope that not only Denmark but the rest of European member states are ready to step up these sanctions,” the Danish premier said.
“It is important that we are very clear about where we stand as a Union, and that we are very clear that we will not look upon threats in a passive way,” she added.
While the Iranian leadership continues to insist its nuclear ambitions are purely peaceful, the compromise Danish plan, under its new EU presidency, aims to give member states six more months to wind up existing contracts with the Islamic Republic.
Italy, Spain and Greece are all big buyers of Iranian oil, with debt-hit Athens relying on easier credit terms from Tehran to finance its purchases.