TORONTO — James Rado just can’t stop fiddling with his “Hair.”

The co-author of the “tribal love-rock musical,” which conquered the world in the late 1960s is working on a series of revisions to the show’s script for its current production here at CanStage, the city’s largest regional theater.

And while that has added a certain level of new interest to the revival opening on March 30, it’s also caused a degree of concern from the musical’s original Broadway producer, Michael Butler.

“I love ‘Hair,’ and I love Jim Rado,” says Butler. “But I wish he’d just leave the show alone.”

“Hair” began Off Broadway on Oct. 29, 1967, as the first offering of Joseph Papp’s Public Theater, directed by Gerald Freedman.

During that run, Butler saw the show and fell in love with it. He was the scion of one of the Midwest’s richest families, but also a committed political activist who had been John F. Kennedy’s adviser on Indian and Middle Eastern affairs.

“I got into ‘Hair’ because I believed in its politics,” says Butler, “and I feel it still has a very pertinent and important message for today.”

After its initial run closed, Butler moved it briefly to a disco called Cheetah, then brought in Tom O’Horgan, who completely overhauled the project, adding 13 songs and cutting much of the book.

Co-writer/thesp GeromeRagni continued in the role of Berger he had originated at the Public, and Rado (who had previously appeared on Broadway as Richard in the original production of “The Lion in Winter”) took over the leading character of Claude.

It opened on Broadway on April 29, 1968, and became an instant hit, running 1,750 performances. Its success was global and, as Butler recalls, “at one point, there were 12 different productions running simultaneously.”

But subsequent revivals have generally been less successful. A 1977 Broadway remount folded after 43 perfs, the 1979 film by Milos Forman was a flop, and a 1993 Old Vic production shuttered rapidly.

In 2001, both Gotham’s Encores! and L.A.’s Reprise restaged the work, but despite initial buzz, plans to transfer either version failed to materialize.

However, in the last year, the political climate surrounding the war in Iraq has heightened interest in the show, with an edgy updated revival at London’s Gate Theater last year, as well as the rewritten Toronto version.

“The parallels are all there,” says CanStage helmer Martin Bragg. “A lot of what happens in the play is eerie. The echoes between Vietnam and Iraq are amazing.”

But Butler feels nothing needs to be changed to keep the show relevant. His response to the Gate production was, “‘Hair’ is about freedom, peace and love. Its lessons are permanent and universal. Even small tinkering is in error.”

Rado insists the impulse for revision began with the current director, Robert Pryor.

“Robert had discovered the original script, with all the scenes Tom O’Horgan cut out during the rehearsals for Broadway,” reveals Rado. “Robert thought it would be valuable for a modern audience to understand more about these characters and their relationships.”

“I was pleased that all these things I had written so long ago that I thought would never be on a stage were now coming to life,” he adds.

Most sources indicate that the changes to the Toronto version are relatively minor, unlike the radical revisionist angle the Gate production took, with specific updated allusions to Iraq and 9/11. The new staging retains the musical’s original time setting, allowing the Vietnam-Iraq parallels to speak for themselves.

And the revisions are even less intrusive than a production earlier this month at Juneau’s Perseverance Theater that included a framing device in which Berger, as an old man, revisited his memories of the past.

It was reports of that staging that prompted Butler to comment that, “I was/am opposed to the changes in the book. ‘Hair’ was made famous by a dedicated group of believers who go way beyond the normal theatrical creators in their dedication to a musical show. Jim Rado has continued to make changes without consideration for the others involved.”

Rado still insists he has the best interest of the work at heart.

“Now it’s a history piece, but it’s also a fairy tale, and maybe we have to tell it in a different way,” he suggests. “You never know what actual effect you’re going to have until you see it in front of an audience.”

Despite his unhappiness with the revisions, Butler plans no action. “I am deeply conflicted about this, because I feel the show’s message needs to be heard today, even more than ever. I desperately want it to succeed, even if I’m not involved.”

“Hair’s” opening number, “Aquarius,” promised that “peace will guide the planets and love will steer the stars,” but it looks as if that elusive moment has yet to arrive for the show’s creators.