The government's controversial shake-up of media laws passed the upper house with the support of rebel Nationals senator Barnaby Joyce and Family First senator Steve Fielding.
The legislation now goes to the House of Representatives where it is expected to pass easily because the coalition government holds the majority of votes.
Senator Joyce, in particular, had raised fears the changes could lead to a loss of diversity.
But the outspoken Queenslander voted for the package after failing to get support for his amendment to improve safeguards governing the minimum number of news outlets in regional areas.
Ownership protection relaxed
The proposed new laws relax ownership restrictions and could clear the way for a merger of Fairfax and PBL, owner of the Nine Network, or a News Limited takeover of a metropolitan television station.
Network Ten immediately welcomed the Senate's decision to change what it said were Australia's outdated existing media laws.
"This has been a very difficult and protracted issue for many years, and we congratulate the government, and in particular Communications Minister Helen Coonan, on achieving this outcome," Ten chairman Nick Falloon said.
The government had agreed to local content concessions demanded by the Nationals to ensure safe passage of the media bills through the Senate.
Chief among those concessions is a ban on one company owning more than two formats - newspapers, television or radio - in any market.
Radio stations will be required to broadcast four-and-a-half hours of local and live content in regional areas a day, and at least 12.5 minutes of local news.
"Without local content (requirements), there would be no support from the National Party," Senator Joyce told parliament.
Senator Coonan will ask the Australian Communications and Media Authority to review the local content requirements to determine if they are appropriate.
Already she has indicated change could be on the cards.
"The government recognises ... that a requirement for four and half hours a day of local content may not be the appropriate level for licensees to maintain commercial viability," Senator Coonan said.
"There is no point at all in legislating local content levels if licensees go out of business in trying to meet them," she added.
Senator Coonan has said the laws are necessary to allow traditional media companies to expand and embrace new technologies.
Labor senator Joe Ludwig said the Nationals had sold out regional Australia by voting for the legislation.
The Australian Democrats said the passage of the media bills was a sad day for the country.
"Why is it better economically and politically for media concentration to be greater in this country than it was, and for there to be less competition at the top level?" Democrats senator Andrew Murray said.