In their bid to solidify support for a new stadium in Arden Hills, the Minnesota Vikings are considering paying more money than the team already pledged to its construction and accept a fixed roof to limit the total cost.

Vikings Vice President Lester Bagley said on Wednesday that the team could "potentially" provide more than its currently offered $407 million toward the proposed Arden Hills stadium. However, no formal announcement is imminent.

As for a non-retractable roof more like the Metrodome's, Bagley said, "we're trying to bring the cost down to make it work. It's got to work physically and financially."

Bagley cautioned that all components of the deal are under discussion and that nothing is final. Since a deal was announced in May, reports have indicated that the overall price has fallen as much as $200 million and the team has boosted its proposed share by $30 million. Bagley said owner Zygi Wilf won't reveal details until a deal is finalized.

The preliminary agreement called for the Vikings to contribute $407 million, the state to add $300 million and Ramsey County to contribute $350 million, largely through a countywide sales tax increase.

Bagley's comments came as the Ramsey County Charter Commission began deliberations on whether a countywide referendum should be required before such a sales tax could be levied.

Andy Cilek, president of the Minnesota Voters Alliance, wants the voters' voices heard on the tax issue. "I'm concerned they're going to move forward without letting the voters vote on it," he said.

St. Paul voters, who make up more than half of Ramsey County's population, soundly rejected a sales tax proposal to build a Twins stadium in 1999.

On Wednesday, the Charter Commission agreed to conduct two public hearings in the next six weeks and to convene immediately after the second hearing a special meeting to vote on ballot language. The language they intend to use as a starting point: "Shall Ramsey County be prohibited from using any revenues, including those raised by taxes or bonding, to fund or assist in funding a Major League Baseball or National Football League sports team or stadium."

No dates were chosen for the meetings.

The question couldn't go to voters until 2012, but commission member Rod Halvorson said he thinks that if the ballot issue moves forward, stadium supporters will find another revenue source instead of the "very inappropriate" sales tax.

Or, he said, if the commission agrees to put it on the ballot, a stadium decision will be "put off until after the vote."

Although the Legislature could vote to prohibit a referendum, Halvorson said he thinks Ramsey County's unique charter would allow it to proceed. Hennepin County wasn't required to have a referendum for the 0.15 of 1 percent sales-tax increase it levied to help pay for Target Field.

Assistant County Attorney Phil Carruthers has said the issue is likely to end up in the courts.

Bagley said the team is meeting weekly with state and county officials to work out details, including road costs and environmental issues. Until everything is done, Bagley said, nothing is done.

Rochelle Olson • 651-735-9749 Twitter: @rochelleolson