"The total abandonment of measures to fight the epidemic in the pre-election period caused the loss of control of the epidemiological situation," doctors said in an open letter.
Hundreds of doctors in Serbia have sounded the alarm after a spike in COVID-19 cases.
Labelling the situation a "health disaster", they have called for the government to sack its coronavirus management unit.
The group of 350 doctors have sent an open letter calling for a probe into the decisions they believe prompted the fresh outbreak.
"The total abandonment of measures to fight the epidemic in the pre-election period (rallies, sports matches, tournaments, celebrations) caused the loss of control of the epidemiological situation and cannot be justified by professional reasons," they wrote.
It comes after the Serbian government last week denied hiding the true impact of COVID-19 in a bid to plough ahead with a parliamentary election.
Cases began rising after the June 21 vote, which saw the ruling Serbian Progressive Party (SNS) win by a landslide.
Serbia went on a strict lockdown on March 15. It eased restrictions at the beginning of May amid public discontent over confinement and despite warnings from doctors it was too early. After a spike in cases after the election, Serbia's president, Aleksandar Vucic, announced a fresh lockdown, which he later backtracked on after protests.
According to the official tally, 491 people have died from COVID-19 in the country of seven million people, but government critics have accused it of playing down this toll.
The Balkan Investigative Reporting Network (BIRN) found Belgrade underreported COVID-19 deaths by nearly 400 between March 19 and June 1.
Doctors behind the open letter added they wanted to speak out "publicly because we see no other solution to the public health disaster in which our country is currently".
The crisis unit swept aside these criticisms.
"Everyone has a right to their opinion," responded epidemiologist Darija Kisic at a press conference. "Unfortunately, we do not see (in the letter) a single name of a doctor who specialises (in the fight) against contagious diseases."
The crisis unit had previously recognised the death toll was "certainly higher" than the official toll because patients may have died without having "been tested".
The Serbian health system is suffering from a massive exodus, especially to Germany, of qualified but underpaid staff. According to the economic information portal novaekonomija.rs, it is lacking 3,500 doctors and 8,000 nurses.