Member countries Italy, Greece and Ireland may be among the first in the eurozone to become insolvent, Der Spiegel reported Friday.
"We have a few countries in the eurozone who are getting into difficulties with their payments," Steinbruck said in Dusseldorf, Germany, this week.
"If one eurozone (country) gets into trouble, then collectively we will have to be helpful," Steinbruck said.
Until Steinbruck made his comments, no other member countries had brought up the possibility of helping other eurozone members out of their financial difficulties, Der Spiegel reported.
The Maastricht Treaty, which underlies the collective currency, prohibits such international altruism, as it seeks to prevent one country from becoming dependent on another, Der Spiegel said.
In Germany, such a suggestion is especially risky. If international help is prorated based on the size of each country's economy, German taxpayers could end up footing one-quarter of the bill when others require help, the report said.
"The euro-region treaties don't foresee any help for insolvent countries but in reality the other states would have to rescue those running into difficulty," said Steinbruck.