The Saskatchewan New Democrats has called for an investigation into Saskatchewan Party MLA Bill Boyd's trip to China earlier this year.

Boyd says it was a personal business trip at his own expense; he was seeking Chinese investment in privately owned Saskatchewan irrigation projects.

However, promotional material in China named Boyd as Saskatchewan Minister of Economy, which Boyd is not.

The Kindersley MLA has already referred the matter to the provincial conflict of interest commissioner for an opinion.

The NDP has asked the commissioner to conduct a full investigation.