OTTAWA — The Canadian Radio-television and Telecommunications Commission is tightening its rules to limit concentration of media ownership.

The changes, announced Tuesday, mean any person or company can own only two of the three different types of outlets -- radio, television or newspapers -- in a single market.

The regulator is also limiting ownership of broadcasting licences to ensure any one group does not control more than 45 per cent of the total television audience share as a result of a transaction.

"The whole thing was a great concern,'' CRTC chairman Konrad von Finckenstein said in an interview.

"Everybody is concerned about it, because the trend is there . . . toward media concentration. On the other hand, we want to make sure there is a plurality of voices and a diversity of programming.''

The regulator also will not approve transactions between cable and satellite companies that distribute television services, which it says would result in one group effectively controlling the delivery of programming in a market.

Von Finckenstein said Tuesday's restrictions do not apply retroactively to existing media conglomerates.

While the new limits restrict ownership of the types of media owned, the rules about how many newspapers and radio and TV stations may be owned have not changed.

Companies can own:

• only one TV station per language in a single market;
• two AM and two FM radio stations in the same language in large markets;
• three radio stations, but only two per frequency band, in smaller markets.

A CRTC spokeswoman said there are no restrictions on the number of newspapers a company can own.

The regulator called for public hearings last March amid concerns Canadian broadcasting was becoming too concentrated following several large consolidations.

The CRTC raised the issue of "diversity of voices'' after CTV's acquisition of CHUM Ltd. and CanWest Global Communication's (TSX:CGS.A) takeover of Alliance Atlantis Communications.

Many of the country's big media companies argue that consolidation is necessary in today's fast-changing media climate, where print, broadcast, newspaper and online operations are converging.

Ian Morrison of the group Friends of Canadian Broadcasting welcomed the CRTC's decision.

"The CRTC is recognizing that as a result of media concentration, there are levels of concentration that could well pose a threat to diversity and, therefore, democracy,'' he said.

"Although I would quibble on some of the details, I think this an example of the CRTC doing its job.''

Others took an opposing view.

The Canadian Media Guild said the CRTC had "blown a chance'' with its ruling to address media concentration in Canada.

"The CRTC is preserving the current unacceptable levels of concentration and is not even adopting meaningful measures to stop it from getting worse,'' stated guild president Lise Lareau in a release.

"By their own admission, they are legalizing the status quo since they admit that their new rules are not being contravened anywhere in Canada.''

Winnipeg-based CanWest, which owns a string of big city daily newspapers from Vancouver to Montreal as well as the Global TV network, declined comment, saying it needed time to review the regulator's decision.

Other media companies, including Torstar Corp. -- parent company of the Toronto Star newspaper -- and CTV Globemedia, which owns The Globe and Mail, did not immediately return calls.