HELENA — A potential ballot initiative that aims to pay landowners if government regulations affect their property could upset the way Montana manages fish and wildlife, potentially costing the state millions of dollars, agency officials said Wednesday.

Bob Lane, head lawyer for the Fish, Wildlife and Parks Department, told the agency’s commissioners that Initiative 154 could force the department to pay landowners affected by hunting and fishing regulations, including the state’s ban on hunting captive deer and elk.

Lane cautioned that his thoughts were only one lawyer’s opinion, adding he found I-154 confusing.

I-154 may not appear on November’s ballot. A Great Falls judge ruled Wednesday that the measure, and two others, should be invalidated due to “pervasive fraud’’ by those who gathered signatures to place the item on the ballot. (See related story on page 1A.)

The initiative would do two things. First, it would limit the use of eminent domain, the right of government to take and pay for private property for public uses. In Montana, certain private companies like utilities and mining companies also have the right of eminent domain, although I-154 does not address those uses.

The initiative would also require both state and local governments to pay landowners if their “property is damaged by the enactment or enforcement of government regulations.’’

Lane said he believed those regulations nclude the number of hunting licenses issued, closures of streams to fishing due to drought or other reasons and the state ban on game farms. He said he could conceive of a situation in which a landowner charged hunters to access their land for elk hunting. If Fish, Wildlife and Parks later concludes the number of elk in the region are dropping and limits the number of hunting permits issued, the landowner could force the department to either pay the landowner for his losses or waive the hunting regulations in that area.

“I think that’s open to a claim,’’ Lane told commissioners at their meeting in Helena Wednesday. “The same could be said of fishing regulations.’’

The initiative also throws into question the ban on game farms, he said.

Chris Smith, the department’s chief of staff, told the commission that even if the agency had to pay just one landowner over hunting and fishing regulations, it could lose some $12 million in federal money.

The commission did not take a formal stance on I-154 Wednesday, but Commission Chairman Steve Doherty of Missoula, said the group will come out with a public statement at its October meeting in Miles City.

Doherty, along with several other commissioners, spoke out against the initiative, while John Brendan, a commissioner from Scobey said he thought the commission should refrain from taking a stance.

Tim Mulligan, a commissioner from Whitehall, said he could imagine the agency paying out landowners for any number of the agency’s regulations, including rules about exotic species, fish ponds, and endangered species.

“It’s frightening,’’ he said.

Trevis Butcher, of Winifred, who is leading the support of I-154, said Lane was wrong on many accounts. First, Butcher said, I-154 would not apply to any existing laws, like the game farm ban.

“That’s the one thing we made certain of,’’ he said. “It’s not retroactive.’’

He also said landowners have no claim over wildlife and the number of hunting permits issued because Montana’s wildlife belongs to the public, not to private landowners.

“It’s an absolute bogus claim,’’ he said.

But Lane said the initiative is so broad, it could be seen to apply retroactively, to laws and regulations already on the books.

A long list of groups, including Trout Unlimited and the Montana Wildlife Federation, has come out against I-154.