SAG and AFTRA’s upcoming film-TV contract negotiations with the AMPTP have gotten a lot messier — with a possible divorce between the performers unions in the cards.

Long perturbed over AFTRA’s refusal to cut back its 50-50 representation on bargaining committees, leaders of the Screen Actors Guild have approved going to SAG’s 120,000 members next month with a referendum that proposes ditching the guild’s 27-year-old Phase 1 joint bargaining agreement.

Saturday’s national board voting was split along geographic lines, with Hollywood reps, who hold 60% of the seats, endorsing the move over vehement opposition from New York and regional reps.

With ballots sent out Feb. 15 and due back by March 31, look for a spirited campaign to unfold quickly. The American Federation of Television & Radio Artists condemned SAG’s move Sunday as “divisive, destructive and clearly not in the best interest of performers in either union” and blasted its proponents as “radical.”

SAG has 120,000 members while AFTRA has 70,000, so the guild has an automatic advantage in persuading its members to back the referendum. About 40,000 thesps are dual cardholders.

Should SAG members approve the referendum, SAG would first attempt to persuade AFTRA to revamp the bargaining committee composition on a 9-1 basis since SAG takes in 90% of the earnings under the contract. Should AFTRA not comply, that would open the door for each union to negotiate its new film-TV contract separately with the Alliance of Motion Picture & Television Producers.

SAG insiders note that the WGA’s film-TV bargaining committee is composed of 14 members from the WGA West and three from the WGA East — in a reflection of earnings generated by each branch. And SAG president Alan Rosenberg said the Phase 1 agreement is archaic.

“Unless we are able to correct the shortcomings of the current Phase 1 agreement, which AFTRA has thus far been unwilling to do, Phase 1 is as out of date as black-and-white television,” said Rosenberg.

The SAG-AFTRA negotiations process is being closely watched by the majors due to fears that thesps may strike this summer. SAG is more closely aligned with the Writers Guild of America than any other Hollywood union, and its members have been supportive of the writers throughout their 11-week strike.

The latest firefight between the performers’ unions reflects ongoing frustration at SAG’s Hollywood branch due to AFTRA’s disproportionate clout at the bargaining table — and tendency to take far less aggressive positions.

The battle amped up in October, when SAG took a blistering shot at AFTRA, accusing the smaller union of poaching contracts on cable shows and shilling for producers by signing deals that exclude a first run of residuals. As part of an outreach to SAG members, the guild detailed instances of performers being paid as much as 53% less under AFTRA contracts for similar work.

That prompted AFTRA to accuse SAG of trying to muscle its way into control of AFTRA and to reiterate its long-held contention that it’s entitled to organize any show within its jurisdiction, and that signing deals at lower terms is preferable to the shows lensing non-union or in Canada.

In answer to a question about how guild members responded to SAG’s outreach on the issue, guild national exec director Doug Allen was unequivocal.

“What we found through multiple set visits, house parties and membership meetings is that actors condemn the reductions in basic cable contracts,” he said. “Actors are very frustrated with AFTRA’s refusal to work with Screen Actors Guild to address the problems we have and to make the joint bargaining relationship more productive for members of both unions.”

AFTRA, in its response Sunday, attempted to portray itself as a victim of a lack of unity among SAG’s leaders.

New York SAG president Sam Freed cast blame on the Hollywood-based Membership First faction for the prospect of SAG and AFTRA negotiating contracts separately.

“I don’t see how that increases SAG’s leverage at the bargining table regardless of how many members of MembershipFirst are on the negotiating committee,” Freed said. “I don’t understand how the current SAG Hollywood leadership doesn’t understand that. They seem to have no coherent plan. ”

“This latest action by SAG is merely a smokescreen for the internal battles between its national membership and a radical Hollywood faction,” it said. “AFTRA will not be a scapegoat for SAG’s internal politics, and we condemn actions by SAG to terminate a joint bargaining agreement that has been working to our members’ mutual benefit for 27 years. AFTRA is prepared to push forward — with or without SAG — to win contracts that provide fair wages, good benefits and safe working conditions for all performers.”

In another development, AFTRA announced Friday that it had agreed to postpone its skedded talks with the AMPTP for the sake of the DGA talks, which launched over the weekend. AFTRA said the majors requested last Thursday to hold off on the start of its talks on the condition that the AFTRA negotiations begin no later than Feb. 19.

AFTRA also said it would extend the Jan. 31 expiration of the so-called network code portion of its contract — which covers a wide variety of TV programming — until March 7.

It’s the second time AFTRA has extended the expiration of the net code. It bumped that date from Nov. 15 to Jan. 31 last year to allow negotiators to focus on the WGA talks.

Current contract, which expires Jan. 31, covers about $400 million in annual earnings from dramatic programs in syndication or outside primetime, daytime serial dramas, gameshows, talkshows, variety and musical programs, news, sports, reality shows and promotional announcements.