Police are "liaising closely" with the Commons authorities over lobbying allegations against Tory MP Tim Yeo.
Scotland Yard said it was in touch with the parliamentary commissioner for standards, but the case had not been referred for criminal investigation.
Mr Yeo stepped aside as chairman of the Energy and Climate Change Select Committee last month after being accused of using his position to further business interests.
He has asked the commissioner to probe claims that he broke rules by offering "coaching" on how to present evidence to the committee, and insisted he expects to be cleared.
A police spokesman stressed the case had not been referred to police for investigation.