Portugal's president warned on Friday that a negative scenario for the country would be if it failed to return to markets as planned in 2014 due to external events or internal politics.

"The incapacity of returning to the markets in 2014 could even be a result of the troika not being ready to sign off in a positive way on the rescue package," President Anibal Cavaco Silva told a conference.

Analysts have warned that a political crisis that hit the country this week could upset the smooth progress of Lisbon's adjustment program under a 78-billion-euro bailout by the European Union and IMF.