April 11 (Reuters) -

Canada's Competition Bureau said on Friday it has started an

investigation into Cigna's ( CI ) pharmacy services unit Express

Scripts' alleged anti-competitive conduct that could prevent or

limit competition in the country's drug retail market.

The agency said it is looking into Express Scripts' alleged

"patient steering" to make people use pharmacies owned or

associated with its Canada unit, instead of a drugstore of the

patient's choice.

The bureau is also looking into practices that are

reducing the margins of its retail pharmacies.

Cigna ( CI ) did not immediately respond to a Reuters request

for comment.

Express Scripts has the largest pharmacy benefit

management operations in Canada, according to the Canadian

Pharmacists Association (CPhA).

The association had

last year

filed a complaint with the antitrust agency alleging

"longstanding and exploitative practices" by the company. It was

not clear if the probe was due to the CPhA's complaint.

Express Scripts provides prescription drug claim processing

and other services for insurance providers and pharmacists and

operates four mail-order pharmacies across Canada, except for

Quebec, according to the agency.

The agency said an order granted by the federal court

requires Express Scripts Canada to produce records and written

information, and provide oral testimony, that are relevant to

its investigation.

There is no conclusion of wrongdoing at this time, the

bureau said.