The Opposition Wildrose has formally asked Alberta's ethics commissioner to investigate an allegedly inappropriate relationship between Alberta Health deputy minister Carl Amrhein and a private health foundation that received ministry funding.

CBC News has previously revealed the close ties between Amrhein and Pure North, a Calgary-based foundation that provides alternative health treatments including high doses of supplements like vitamin D.

Amrhein participated in the Pure North program while deputy minister.

Several sources told CBC News he also lobbied Alberta Health for more funding for Pure North while in his previous role as official administrator of Alberta Health Services.

While provost of the University of Alberta, Amrhein provided two letters of support for Pure North, one of which the foundation used in its appeal to the government for public funding.

In October 2016, Amrhein signed, on behalf of the ministry, a $4.2 million grant with Pure North for a nurse-practitioner-led, primary care clinic.

Ethics Commissioner Marguerite Trussler said Amrhein told her the decision on funding Pure North was made elsewhere and he merely signed the agreement in his capacity as deputy minister, after the minister had signed off.

Full investigation

In a letter dated May 16, Wildrose accountability critic Nathan Cooper and health critic Tany Yao asked Alberta's ethics commissioner to launch a full investigation into Amrhein's relationship with Pure North, if she has not conducted one already.

"Albertans want to know that decisions aren't being made within the health department because of personal relationships or cronyism," Cooper said in a news release.

"It's our hope that the ethics commissioner will accept our call for an investigation and get to the bottom of what's really happening with the deputy minister of health and Pure North."

A health ministry spokesperson has told CBC News that Amrhein "fully disclosed" his relationship with Pure North to Alberta's ethics commissioner when he became deputy minister in August 2015.

Trussler told CBC News that Amrhein disclosed his participation in the Pure North program when he became deputy minister.

But she could not say whether Amrhein had disclosed anything else about his relationship with the foundation, saying she was legally bound to disclose only what Amrhein had given her permission to disclose.