David Cameron could be hauled in front of MPs to explain his resignation honours list after the chair of a Commons committee called for an investigation into the controversy.
The former Prime Minister was accused of cronyism after he dished out gongs to a string of political allies, Tory donors and Downing Street staff.
Bernard Jenkin, chair of the Public Administration and Constitutional Affairs Committee, has invited its members to probe Mr Cameron's resignation honours and his nomination of 13 new peers, when Parliament reconvenes in September.
The cross-party group of MPs could summon Mr Cameron as a witness and subject him to a public grilling as part of any inquiry.
In 2012, the committee recommended that a "far higher proportion" of honours should be awarded to "people who devote their time to the local community, instead of to politicians, civil servants, and celebrities".
Its report expressed concerns that political considerations influence the awarding of honours, and recommended that the process should be independent of the PM, but this was rejected by the coalition government.
It came after the chairman of the Committee on Standards in Public Life, Northern Ireland academic Lord Bew, said the list of 59 Cameron nominations for peerages and gongs "has to be the last one, given the public outcry".
Calling for a new inquiry, Mr Jenkin said: "We have already discussed the principle of holding an inquiry into the House of Lords.
"This should include the size and composition of the House of Lords, but also the way in which new peers are appointed."
In his resignation honours, Mr Cameron created 13 Tory life peers, giving the Tories 207 - one more than Labour.
Tory treasurer, Andrew Fraser, and political aides, Gabrielle Bertin and Camilla Cavendish, who both worked at Number 10, were all given peerages.
Samantha Cameron's stylist Isabel Spearman received an OBE for political and public service.