Ecuador investigators raided the health ministry on Wednesday as part of a probe into influence peddling against former health minister Juan Carlos Zevallos.
Zevallos resigned last month over a vaccine scandal that saw well-connected individuals, including his mother, jump the queue for their coronavirus jabs.
"In the operation, information is being collected on the vaccination plan and the list of beneficiaries" of immunization against Covid-19, the public prosecutor's office said on Twitter.
When resigning, Zevallos admitted that his 87-year-old mother and "several" others close to him had received a shot among the 42,000 doses of the Pfizer-BioNTech vaccine the country had reserved for workers in health care and old age homes.
Last week, Zevallos's successor, Rodolfo Farfan said that the ministry had sent a list of those to have received the vaccination to the public prosecutor's office, which claims that the list is incomplete.
Ecuador is not the only country to have been embroiled in vaccination queue-jumping scandals.
Peru and Argentina have also been hit by outcries over the rich and powerful getting their coronavirus jabs out of turn.
Ecuador has faced delays in rolling out its immunization program that began in January.
Just 119,000 people have so far received the first dose of the Pfizer jab.
The country of 17.4 million has registered more than 305,000 coronavirus cases and 16,300 deaths.
The government of President Lenin Moreno claims to have negotiated the purchase of 20 million vaccine doses and plans to immunize 10 million people.