This comes on top of the 20 fines sent out last month.
The Met Police are not providing details of who will be sent a fine or about the events.
But Downing Street has said it will confirm if Prime Minister Boris Johnson and top civil servant Simon Case are among the recipients.
Those who receive fines can either pay within 28 days or contest the police decision.
If they contest the fine, police will review the case and then either withdraw the penalty or take the matter to court.
In a statement, the police said they were “making every effort to progress this investigation at speed”.
The police are investigating 12 events that may have breached Covid lockdown rules in government buildings, including at least three attended by Mr Johnson.
As part of their inquiry, they have sent out over 100 questionnaires to ask about people’s participation in the events.
Reports of gatherings in Downing Street and Whitehall during the pandemic led to several Conservative MPs called for the prime minister to resign.