Bolivia first closed its border with Brazil on April 2, with provisions for cross-border trade, and was to lift the ban on Friday, reports Xinhua news agency.
"An epidemiological evaluation has been made on the border with Brazil and we consider it necessary to extend the closure for another week," Deputy Foreign Trade and Integration Minister Benjamin Blanco said.
"At the end of this period we will return to work on the situation in the border regions to take action," he added.
Bolivia has also taken more general measures to curb the outbreak, including requiring visitors to show the negative results of a recently-taken Covid-19 test.
A year and a month since the first two cases of Covid-19 were detected in Bolivia, the Ministry of Health said the country's overall caseload and death toll stood at 279,207 and 12,412.