OTTAWA - The federal ethics commissioner has rejected a request to investigate Prime Minister Stephen Harper's Mideast adviser.

The group Democracy Watch had asked Bernard Shapiro to probe MP Wajid Khan on two grounds -- his switch to the Conservatives from the Liberals and his refusal to release a report he had promised to make public.

But the organization says Shapiro has refused to address its complaint because applicable rules in the MPs code are "not enforceable.''

Khan joined the Tories in January after working for months as Harper's adviser on the Middle East and Central Asia.

He took a 19-day tour of the Middle East in September and said he would provide fellow MPs with a report.

However, he later refused to release the report, and Harper's office has said it will remain confidential.