Vote counting has begun in Paraguay's presidential election. The outcome of Sunday's vote could determine the fate of the country's relationship with Taiwan.

Opinion polls suggest a close two-way contest between right-wing ruling party candidate Santiago Pena, who is a former finance minister, and centrist opposition coalition candidate Efrain Alegre.

Paraguay is one of 13 countries that has diplomatic ties with Taiwan, and the only remaining one in South America.

One focal point in the presidential race is the country's relations with Taiwan.

Pena supports maintaining ties with Taiwan, while Alegre has hinted at severing relations and seeking to open diplomatic ties with China to boost exports of agricultural products, such as beef and soybeans.

In recent years, a number of Latin American countries have established diplomatic relations with Beijing, including Honduras, which cut ties with Taiwan in March.

Preliminary results are expected as early as Sunday night.