Police and prosecutors are still examining the expenses of three parliamentarians, it has been disclosed.
A panel consisting of senior figures from Scotland Yard and the CPS is considering whether further action should be taken in the cases.
One of those involved is believed to be Labour minister Denis MacShane, who was referred to police by the parliamentary standards commissioner in October 2010.
Tory backbencher David Amess has also said he has spoken to officers about his claims. Both men deny any wrongdoing.
Four ex-MPs and two peers have already been sentenced to prison terms for expenses abuses.
Another former MP, Margaret Moran, has been charged and proceedings are ongoing.
A CPS spokesman said: "In 2009 the Director of Public Prosecutions and the then commissioner of the Metropolitan Police set up a panel, which consists of senior prosecuting lawyers and senior police officers.
"The panel considers and assesses complaints relating to parliamentary expenses and whether there should be a criminal investigation.
"The panel is currently considering matters relating to three individuals."