It had a 43-passenger capacity, according to the transport ministry.
On Wednesday police said there were as many as 178 people missing, which if confirmed would make it one of Indonesia's worst maritime disasters.
Authorities have been relying on families who have reported that missing relatives may have been on the doomed vessel.
Later at a press conference, Syaugi added: "There are many people who have reported their relatives missing, but whether they were on the boat or not we don't know." So far, four bodies have been found and another 18 people rescued, according to the local disaster agency, as the search turned to recovering the bodies of victims -- including those still trapped inside the sunken boat.
"We'll be here until they find my brother's body," said Nurhayati, among hundreds of grief-stricken people waiting by the shore for updates.
"We just want to see his body and take him with us."
A sobbing Suwarni pleaded for news of her son and his fiance, both believed to have been on board.
"Why are the rescue teams so slow?" said the 55-year-old, who like many Indonesians goes by one name.
"I'm so disappointed -- there's no progress here. Please bring back my son." Authorities have deployed divers and underwater vehicles, along with about 400 personnel, to search the enormous lake in an operation expected to last at least a week.
Lake Toba, popular with international and domestic tourists, fills the crater of a supervolcano that erupted tens of thousands of years ago.
It is one of the world's deepest lakes and extends some 1,145 square kilometres (440 square miles).
"We are looking to search as deep as 400 metres but we haven't found anything yet because the area is very large," said the rescue agency's Syaugi.
Images from the scene Wednesday showed rescuers covering up the bloated body of a woman who had washed ashore.
It was not clear if any foreigners were on board the ferry or what caused the disaster.
Enforcement of safety standards also tends to be weak.
(This story has not been edited by Devdiscourse staff and is auto-generated from a syndicated feed.)