Nearly 4,400 burials occurred in March, 40 percent higher than any month since at least January, 2018, according to a Reuters review of statistics from the city's Department of Parks and Cemeteries. The second-highest total during that period was March 2019, when nearly 3,100 people were buried.
Reuters was able to obtain statistics going back to the start of 2018.
The city has been at the epicenter of novel coronavirus infections in Indonesia, accounting for 971 cases and 90 deaths, according to central government data, or roughly half the country's total for both.
Jakarta's governor, Anies Baswedan, and some public health experts suspect the number of infections and deaths in Jakarta has been significantly under-reported due to one of the world's lowest rates of testing.
"It is extremely disturbing," Baswedan told Reuters on Friday, referring to the funeral statistics. "I'm struggling to find another reason than unreported COVID-19 deaths."
A senior health ministry official did not respond to phone calls and messages requesting comment on the funeral statistics. A spokesman for President Joko Widodo did not respond to requests for comment.
The figures from Jakarta's Department of Parks and Cemeteries do not identify the cause of death, but no other new epidemics have been reported in Jakarta over the period and nor were there any major natural disasters.
Indonesia has almost doubled tests in the past week but has conducted only 7,621 tests in a country of more than 260 million people.
As of Friday, the health ministry reported the total number of infections in Indonesia was 1,986. Deaths from COVID-19 were 181, the most in Asia apart from China.
In an interview on Thursday, before Baswedan had made his comments, Achmad Yurianto, a senior health ministry official, defended the reporting and testing system.
He said the central government based its data on lab results using the accurate polymerase chain reaction (PCR) method. He did not respond to requests for comment on the funeral figures.
Hospital staff and undertakers in Jakarta have taken special precautions with the bodies of 438 people they suspect died from COVID-19 between March 6 and April 2, according to the governor's office.
The protocols mean undertakers disinfected and wrapped the bodies in plastic rather than fabric as Islamic customs requires. Indonesia is the world's most populous Muslim majority country.
Indonesia is combatting the outbreak of novel coronavirus by introducing social distancing policies, but President Joko Widodo has opposed the harsh lockdown measures adopted in many countries including Indonesia's neighbors.
Widodo has said that he wants to protect the poor from economic dislocation and believes Indonesians lack the discipline to embrace tough quarantine measures.
Baswedan, a political opponent of Widodo, has imposed tougher measures in Jakarta, where he has declared an emergency and schools and many shops and businesses are shut.
But his call for a ban on bus travel from Jakarta to other parts of Indonesia in an effort to stop the spread of the virus has been rejected by the national government.
Amid fears that an annual exodus to homes across the archipelagic nation for the Muslim Ramadan holiday would accelerate the outbreak, Indonesia announced on Thursday it would give cash to poor families to stay in Jakarta instead.
However, the government rejected calls for an outright ban on "mudik," as the holiday is known locally, because it did not want to introduce draconian measures.
The novel coronavirus has already spread beyond Jakarta. It has been detected in 32 of the country's 34 provinces and, as of this week, most cases are outside Jakarta, according to central government data.