AURORA, Colo. -- A Senate committee hearing on immigration, headed by Colorado Republican Wayne Allard, triggered a debate before it got started Wednesday when critics questioned its purpose and the list of invited witnesses.

Allard, member of the Senate Budget Committee, has said he wants Colorado to have a voice in the immigration debate and wants to pin down how legislation pending in Congress will affect state and local budgets and personnel.

Critics, including Sen. Ken Salazar, D-Colo., have derided the hearing as nothing more than election-year politics. Cody Wertz, Salazar's spokesman, said Salazar wasn't invited.

Neither Allard nor Salazar is up for election this year.

"The time for informative field hearings was last year, before the House and Senate passed bills," Rep. Mark Udall, D-Colo., said. "At this last stage, field hearings look more like a cheap political stunt than an honest attempt at crafting legislation."

The committee spoke about significant costs of illegal immigration in the state of Colorado.

They also addressed the impact on budgets if either the current senate or house immigration bills pass. Some said they believe a senate version would be much costlier.

Robert Rector of the Heritage Foundations said the U.S. already foots the bill for millions of low skilled, native-born Americans.

"What we're really confronting here is whether we can afford that similar level of generosity for large numbers of millions and millions of people coming here from the third world," said Rector. "And the simple answer is, no of course, we cannot. This is a recipe for fiscal disaster."

"What we need to do is slow that rate of growth and finally slow the number of persons who are legally coming across the borders of the United States," said Gov. Bill Owens.

Owens said he wants to deal with illegal immigration in a humane and caring manner but worries about the increase in undocumented workers. He said we have a quarter of a million undocumented workers already and he is concerned about what will happen when that number becomes half a million.

Outside the hearing, immigrant advocates carrying a banner saying "No human being is illegal" protested that they were not allowed to speak. About 10 to 15 anti-illegal immigration protesters carried signs saying "Born in America."

Gabriela Flora of the American Friends Service Committee called the hearing a political stunt.

"This is not a hearing that is looking for solutions," she said. "One of the ideas is to raise anti-immigrant fervor to get out the extremist voters."

Frosty Wooldridge, wearing a T-shirt saying "stop illegal immigration," yelled back that the invasion of foreign workers must be stopped.

Allard voted against a bill that passed the Senate in May that would create a guest worker program and give illegal immigrants a chance to earn citizenship. Spokeswoman Laura Condeluci said the senator felt the guest worker provision amounted to amnesty for illegal immigrants.

A House bill would make illegal immigrants subject to felony charges. Both measures would build a security wall along parts of the U.S.-Mexico border.

Carlos Espinosa, spokesman for Rep. Tom Tancredo, R-Colo., said the field hearings are valuable in helping Congress determine what will work and what won't in reforming immigration.

"They have swayed some decision-makers about what's a workable compromise," Espinosa said.

Tancredo, an outspoken foe of illegal immigration, headed a House Resources Committee hearing on the issue Monday in Hamilton, Mont. He didn't plan to attend the Colorado hearing.

Some Colorado activists complained that they weren't allowed to speak at the hearing. Lisa Duran, executive director of the immigrant advocacy group Rights for All People, said she was told she could submit written comments.

"I believe that when you have a hearing such as this one and the only testimony is from people from a very particular set of perspectives, it's not productive to finding solutions," Duran said. "We have a broken system and people are suffering because of it, and I don't think Sen. Allard cares."

Robert Copley Jr., a Colorado member of the Minutemen, said local groups weren't being included. He called it a town meeting where the town was not invited.

An Allard spokesman said the speakers for the vent had to be approved by the Senate Budget Committee.

Condeluci said several people contacted Allard's office after the list of speakers was completed. She said the senator will take any written comments back to Washington.

Those signed up to speak included Owens, Aurora Mayor Ed Tauer, local law enforcement officials and Helen Krieble, owner of a Colorado equestrian park who authored a leading guest worker proposal.