An answering machine was the only response AFP obtained from the Portuguese embassy.
According to Swiss daily La Tribune de Geneve, the monthly salaries of the 56 Portuguese diplomats in the country have fallen from 4,500 to 3,000 francs ($5,500 to 3,700) after their government's recent decision to lower all public salaries by 10 percent and the rise of the franc against the euro.
The Swiss franc, considered a safe haven currency, has been rising throughout the year as investors fled economic turmoil abroad. At its peak earlier in August it was up around 20 percent against the euro compared to 2009.
"This situation is unacceptable," the newspaper quoted Alexandre Vieira, the assistant secretary-general of the union of Portuguese diplomats.
The newspaper added the diplomats, who began their strike Monday, had sent a letter to the Swiss minister of foreign affairs Micheline Calmy-Rey to explain the situation and seek help.