Portugal's Prime Minister Antonio Costa has tested positive for COVID-19, his office said in a statement on Tuesday.

The prime minister has no symptoms and will be in isolation for seven days.

"The prime minister carried out a routine self-test for COVID-19 today and had a positive result," the statement said.

"This result has already been confirmed by an antigen test.”

According to the statement, the prime minister has informed President Marcelo Rebelo de Sousa of his situation.

Over the course of the last two weeks, Costa held campaign rallies and events across the country, usually attracting massive crowds.

Portugal's ruling centre-left Socialists won an outright parliamentary majority on Sunday securing the 60-year-old his third mandate with 117 parliamentary seats – the Socialist Party's only second full majority in Portugal's democratic history.

(With input from agencies)