A group of Canadian senators wants to find out if a growing concentration of ownership is reducing the range of voices in the country's media.

The six senators have set up a steering group to launch a study of the effect of media concentration on freedom of information.

Senator Laurier Lapierre says the move was spurred by CanWest Global's decision to publish national editorials throughout its Southam newspaper chain.

All papers in the chain must carry the editorial and they're not allowed to write any of their own that take a different point of view.

"That disturbed me to no end," says Lapierre. "I said to myself now if that's the case with newspapers, what's to stop them from doing that with the television stations?"

Two big owners

CanWest owns several big city daily newspapers. It's also the country's second biggest private broadcaster after CTV. The BCE group owns CTV and controls The Globe and Mail.

The senators intend to set up a full Senate committee to study the issue.

Last week, a group of prominent Canadians including Margaret Atwood, David Suzuki and Matthew Coon Come called on the government to investigate media concentration.

Historian Jack Granatstein was also among those calling for an inquiry but he wonders if there's anything the government can really do. "Anything the government will propose will be closing the barn door rather late," he said.

The senators hope to begin their public hearings in the fall and publish their findings shortly after.