"We've now recorded 761 people from three villages falling ill after eating buffalo meat infected with anthrax," said local official Cornelis Wara from Ende district, one of the affected areas on Flores island.
A veterinary official, Maria Geong, said more teams had been sent to the district to locate and vaccinate livestock, reinforcing several sent at the weekend after 20 villagers were initially reported ill.
"We have sent 20,000 doses of vaccine to the three villages and several areas in Ende district," she said, adding that another 20,000 doses had also been sent to adjacent Sikka district to contain the spread of the disease.
In April, five people died after consuming infected beef on nearby Sumba island. Health officials sealed off a number of villages there for several weeks to contain the disease.
Anthrax is an acute infection that usually only afflicts livestock but it can be transmitted to humans who handle or eat infected animals.
Flores and Sumba are in East Nusa Tenggara province, where anthrax is endemic. The province is 1,500 kilometres (930 miles) from the capital, Jakarta.