The parliamentary ethics watchdog is rejecting a Conservative complaint about union advertising and sponsorship at the NDP convention.

The Tories wrote the conflict-of-interest and ethics commissioner in the summer, alleging that advertising at the June convention helped bankroll the event and was targeted at NDP members.

In short, the Tories said the union ads constituted a gift or benefit to New Democrat MPs.

But commissioner Mary Dawson says she received no additional information from the Conservatives to support their allegations, and could only go on details provided by the NDP.

The NDP told her the unions paid full commercial value for ads at the convention, and the transactions were arranged by the party's director of fundraising.

Dawson says MPs were not involved in the deal, and she has no reasonable grounds to believe they violated the conflict-of-interest code.