Congo’s deputy health minister has accused cabinet members of receiving kickbacks on government contracts for the coronavirus response while health workers went unpaid for months.

Albert M’peti Biyombo told Reuters on Wednesday that a confidential letter from him to the prime minister dated June 29, which was widely shared on social media, was authentic, adding: “I don’t know how it got out.”

The letter accused unnamed members of the cabinet of colluding with networks within the health ministry to embezzle funds from the government and its aid partners even as state hospitals lacked drugs and basic equipment.

The allegations are likely to worsen a standoff over pay with those responding to the coronavirus epidemic in Democratic Republic of Congo.

Last week, health workers in the capital Kinshasa began a partial strike in protest at not being paid bonuses for months.

“These mafia networks require kickbacks of up to 35% from structures benefiting from these funds,” Biyombo said in the letter, where he recalled a previous request for a financial audit of the response.

He said that Health Minister Eteni Longondo had signed off large disbursements of funds – for ambulances, beds and other medical equipment – without seeking his deputy’s counter-signature, overriding government procurement rules.

Longondo did not immediately respond to a request for comment.

“I am regularly under pressure to sign non-priority and unrelated financial documents,” Biyongo said. He pointed to examples including the payment of medical fees for coronavirus treatment at a hospital not designated for free care by the government.

Since confirming its first case of coronavirus in March, Congo has recorded over 7 700 cases, overwhelmingly in Kinshasa.

But health authorities say a shortage of test kits and widespread stigmatisation around testing mean the true number of infections is likely to be far higher.

In March, Longondo’s predecessor Oly Ilunga was sentenced to five years of forced labour for embezzling more than $400 000 from Ebola response funds.