A petition that's being circulated could stifle efforts to expand the Austin Convention Center.

Unconventional Austin, a recently formed political action committee, is promoting the petition, which would require voter approval in advance of any expansion or upgrades to the convention center that cost more than $20 million, according to a copy of the petition obtained by the American-Statesman.

Last week, the Austin City Council approved a broad resolution offered by Council Member Kathie Tovo that included support for a $1.2 billion expansion of the convention center.

"Our petition would prioritize public support for the people and places that make Austin a unique and authentic tourism destination, many of which we are at risk of losing — live music and musicians, arts and culture, our history, iconic local businesses and our environment," said a statement from Unconventional Austin officials Sylvia Pedley, Bill Oliver and John Riedie, who is a member of the city's Tourism Commission.

"We do not oppose expansion of the Convention Center but believe the public should vote on any expansion and that public dollars for the expansion should be limited so that we can prioritize and invest in those things that make Austin unique."

On top of requiring voter approval for virtually any expansion of the facility, the PAC's petition calls for sharp decreases to the amount of hotel taxes the convention center receives each year. The convention center and its marketing arm, Visit Austin, get about 70% of the city's hotel taxes collected each year. The convention center received about 64% of hotel taxes collected last year, according to city documents.

The petition ordinance would cap the center's share of hotel taxes at either 34% or five times the amount of hotel taxes directly attributed to events at the convention center, whichever figure is greater. The petition states that less than 4% of hotel taxes collected annually are related to events at the convention center. A 2013 report compiled by the city put that number at 2%.

Austin Convention Center officials did not return calls or respond to emails seeking comment.

The plan approved last week by council members envisions expanding the convention center to the west before demolishing and rebuilding a portion of the facility within its existing footprint over six city blocks downtown. It was the most expensive option put forth in a recent University of Texas architectural study.

The proposed ordinance would split 30% of hotel tax revenue between cultural arts and historic preservation. The remainder would be directed toward promoting the arts, tourism-related transportation and live music venues.

The petition, which was circulated by canvassers in the Mueller development Wednesday, also revisits gripes about the City Council's approval of building a Major League Soccer stadium in North Austin on city-owned land. The document states that any expansion of the convention center would be subject to property tax.

State law allows home-rule cities to create the rules governing petition elections. However, the general rule applied to most cities, including Austin, is that petition organizers must gather signatures from either 5 percent of a city’s registered voters or 20,000 people, whichever number is smaller. In Austin, the 20,000 signatures requirement accounts for fewer than 3 percent of the city’s registered voters.