It’s one of Hollywood’s longest-running battles — unions seeking to expand their turf amid seemingly intractable opposition from studios, netsand producers.

These days, however, the lines in the sand are being drawn on two disparate fronts: videogames and casting. The outcomes could well determine the unions’ future role in Hollywood’s growth areas.

In the vidgame realm, SAG and AFTRA are threatening to strike to expand their jurisdiction beyond a decade-old contract that covers earnings of just $5 million of work per year of the estimated $6 billion a year business. They’re betting vidgame producers won’t want to create new games without big stars, so non-signatories will have to play ball.

Strike authorization ballots are due back June 7. SAG’s negotiating committee has already recommended a $5,000 fine and suspension for any guild member who works on an interactive game during a work stoppage.

Meanwhile, the Teamsters find out June 23 the results of an election determining whether they will represent 300 casting directors. Vote follows a contentious three-year effort in which the Teamsters threatened last winter to close down every U.S. production if the casting directors weren’t allowed to unionize.

The skirmishes point up a growing sore spot for the unions: As jobs in traditional media dry up, they need to stake their claim for jurisdiction over new and hybrid media forms.

Reality TV remains a particular sore point.

Both the WGA and DGA tried but failed last fall to expand their jurisdiction into reality TV. Negotiators concluded their members wouldn’t be willing to strike over the issue.

It’s a particularly brutal world for writers. Producers of reality fare don’t want to destroy the audience illusion by acknowledging in the credits that their shows are scripted in outlines. So they won’t label those who perform those tasks as writers, opting to use terms like “story producers,” “story editors” and “segment producers.”

The DGA made inroads on “Last Comic Standing,” “Fear Factor” and “Celebrity Mole”; IATSE has achieved coverage for below-the-line employees on “Blind Date,” “The Swan,” “Big Brother,” “Next Action Star,” “American Idol” and “Queer Eye for the Straight Guy.”

Despite devoting “significant resources” to organizing, the WGA’s success in the reality or hybrid arenas has been limited to one show: HBO’s “Curb Your Enthusiasm,” which is largely improvised by actors.

There are still plenty of areas beyond reality TV that aren’t covered by one of Hollywood’s major guilds, including writers for animated features; cable news and talkshows; home repair/makeover shows; Spanish-language shows; and some commercials jobs. And then there’s the realm of moderately budgeted pics and TV shows, often shot outside Los Angeles and New York.

Getting those areas organized is a daunting task; even members in good standing often are willing to risk violating their guild mandates in order to land jobs.

Of course, studios and producers have no interest in ceding jurisdiction, since doing so virtually ensures their costs will increase at a time of relentless pressure on the bottom line.

One tactic that particularly irks the guilds: producers setting up a separate company for a specific production so that by the time a union can organize the employees, the production’s finished.

In a sign of how brutal these battles can be, SAG publicly embarrassed Jon Voight last winter after he was nominated for a SAG award for his perf in “Mitch Albom’s The Five People You Meet in Heaven.” Voight was notified he would not be invited to the awards ceremony because he had resigned previously from the guild. The thesp was picketed two years ago by SAG when he shot a non-union film, “A Deadly Course.”

SAG’s Rule One explicitly bars its members from working for nonsignatory producers. During the 2000 commercials strike, SAG fined Elizabeth Hurley and Tiger Woods for working non-union and expelled seven members and banned 75 nonmembers for up to five years. But working non-union is so pervasive that SAG can discipline only a small percentage of offenders.

With Hollywood’s ongoing expansion into new areas of revenue generation, such conflicts are only likely to escalate.