Karel Schwarzenberg, whose country holds the EU presidency, spoke after meeting with his South African counterpart Nkosazana Dlamini-Zuma and the EU development commissioner Louis Michel outside Cape Town.
"The European Union is contemplating the implementation of further restrictive measures," he said.
"The sanctions, we have not yet decided about them. They would be what we call tailor-made — not hitting the broad population but hitting those who are responsible and in power," Schwarzenberg said.
The EU last month widened sanctions on Mugabe’s government, including a travel ban on his inner circle.
The EU also expressed deep concern about human rights violations, a cholera epidemic that has claimed 2,100 lives, and "the tendency of Robert Mugabe to make unilateral decisions," Schwarzenberg added.
The former southern African breadbasket on Friday announced it was issuing a 100 trillion dollar note in a bid to keep pace with hyperinflation, which has impoverished the once-vibrant country.
Mugabe signed a power-sharing deal with opposition leader Morgan Tsvangirai four months ago, but their agreement to form a unity government has never been implemented, despite a worsening humanitarian crisis marked by severe food shortages.
"The best agreements, the best laws are totally senseless if they are not implemented," Schwarzenberg said, adding that the unity accord "is the only starting point we have to the process of democracy and rule of law in Zimbabwe."