Labour leader Ed Miliband took the opportunity of the furore over donations and the angry response to last week's Budget to rally Labour troops at their weekly meeting.
In an unscheduled behind-closed-doors address to MPs and peers, a spokesman said he had told them it had been a "politically significant week".
Labour said the addition of the names of Chequers guests to the list took the total they had given to the party since Mr Cameron became leader to more than £23 million.
Labour has raced into a poll lead as the Tories deal with fall-out from the Budget and the cash-for-access controversy, a survey shows.
The Tories have released a list of party donors who attended a lunch with the PM, with Labour calling for an independent inquiry.
A look at the Conservative party donations and who paid them