German Finance Minister Wolfgang Schäuble | Rolex Dela Pena - Pool/Getty Wolfgang Schäuble to Portugal: Listen to EU warnings

Portugal should heed European Union warnings about its financial stability, German Finance Minister Wolfgang Schäuble said Monday, as fears grow that the country could need another bailout.

"Portugal must listen to the European Union warnings with regard to public policies," Schäuble said on his way into a meeting of the Eurogroup of eurozone finance ministers in Brussels.

His advice comes as the German government and the European Commission fear that Lisbon is edging perilously close to needing another rescue package from the EU, Der Spiegel reported Friday.

The German finance ministry later denied that Portugal will need a second round of help.

"There is no need for a new ESM [European Stability Mechanism] rescue program," said a spokeswoman for the finance ministry, adding that Portugal successfully implemented structural reforms to improve its competitiveness and "it's important that the current government continues with these successful economic policies."

Michel Roth, the German minister for European Affairs, said Monday that he has not seen any differences in approach since the Socialist António Costa replaced the conservative Pedro Passos Coelho as Portugal's prime minister.

Portuguese bond yields rose above 3 percent on Monday after the credit rating agency Fitch revised the country's outlook to stable from positive, saying that "the need to implement further austerity measures during 2016 or in the 2017 budget could prove a breaking point for the [government] coalition. Renewed political uncertainty would increase fiscal and macroeconomic downside risks."