By John Poirier and Diane Bartz - Analysis

WASHINGTON (Reuters) - Comcast Corp's <CMCSA.O> NBC Universal deal faces a long and intense regulatory review that could end in approval only after the cable giant agrees to give rivals access to NBCU's television shows and movies, experts said on Thursday.

The U.S. government's concern will likely focus on ensuring that Comcast's cable and satellite competitors, like Verizon Communications Inc <VZ.N> and DISH Network Corp <DISH.O>, have access to NBC Universal's programs for their subscribers.

Herb Kohl, a Democrat who chairs the Senate's antitrust and competition policy subcommittee, called on regulators to "ensure that all content providers are treated fairly on the Comcast platform."

Kohl said he will hold a hearing to look at how the Comcast deal could affect consumers' access to diverse programing, especially on the Internet.

"It's critical that we preserve robust competition and promote innovative and emerging program delivery in this rapidly changing market," he said in a statement.

Comcast and General Electric Co <GE.N> unveiled their NBC Universal deal on Thursday, planning to set up a joint venture that is 51 percent owned by Comcast and 49 percent by GE. The deal would give Comcast, the top U.S. cable service provider, control of a major media conglomerate.

Antitrust experts said it could take the U.S. Federal Communications Commission, which reviews broadcast license transfer applications, and Justice Department or Federal Trade Commission, which share the job of antitrust regulation, a year to work out conditions for approval, but they expected the deal to finally get the green light.

"I think it will get to closing. I don't think anybody's going to stop the deal," said antitrust expert John Briggs of the law firm Axinn Veltrop Harkrider LLP.

Public interest groups, nonetheless, have urged the Obama administration to keep its commitment to reinvigorate U.S. antitrust laws by making sure the proposed deal doesn't see the light of day.

They fear that Comcast might charge other cable distributors higher fees to transmit NBC Universal-owned content, leading to higher cable bills. They also fear other media M&A deals could result in less competition.

"There are no indications that this merger could be good for the public in any way," Free Press policy director Ben Scott said in a statement. "It will lead to higher cable bills, fewer independent programing choices, and less competition. The only party standing to benefit here is Comcast -- at the expense of the public."

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