The final push is on at the Capitol for state legislators to fund a critical piece of the $1.79 billion Southwest light-rail project, and powerful Twin Cities business interests have now publicly entered the fray.

The Metropolitan Council, which would build and operate the 14.5-mile line, needs to nail down the final 10-percent portion of local matching funds (about $135 million) from the state Legislature this year. Time is short — the current session ends May 23.

“We have 13 days to go,” said Sen. Scott Dibble, DFL-Minneapolis, chairman of the Senate Transportation Committee, at a transit roundtable meeting Monday in Eden Prairie. “It’s time now to fish or cut bait” on a comprehensive transportation package that includes funding for Southwest.

The state’s share for Southwest would mean the project would qualify for $895 million in matching funds from the Federal Transit Administration. If the final funding piece is extracted from the Legislature, Southwest will likely open for service in 2020. If not, the fate of the Twin Cities’ third light-rail line is uncertain.

As the deadline looms, a group of corporate leaders penned an opinion piece in the Star Tribune on Saturday that urged legislators to pass a bipartisan transportation bill this year, including funding the Southwest, the Bottineau Blue Line LRT and other transit projects. The letter doesn’t specify where the state funds should come from.

“Right now, there are more than a billion dollars on the table from the federal government to realize these transit projects,” said the article, credited to chief executives Richard Davis of U.S. Bancorp, Scott Wine of Polaris Industries and Doug Baker of Ecolab. “These federal funds cannot be used for roadway or highway systems, and we will receive them only if the state dedicates its portion of local funding.”

Corporate chiefs from Allina Health, Best Buy, Children’s Hospitals and Clinics, General Mills, Land O’Lakes, Mortenson Construction, Target, Wells Fargo and Xcel Energy also signed on to the missive.

Business groups, such as the chambers of commerce in Minneapolis and St. Paul, the TwinWest Chamber of Commerce and the Eden Prairie chamber, have announced their support for the line, as well.

The Minnesota Chamber of Commerce, which represents statewide business interests, doesn’t weigh in on specific transportation projects, but supports overall investment in roads, bridges and transit systems, said spokesman Jim Pumarlo.

Supporters are pushing for a metro-area sales tax to help build Southwest and other metro transit projects, such as the $1.5 billion Bottineau line, which is slated to open in 2021.

Most of the legislators, local government officials and business interests attending Monday’s roundtable appeared to support Southwest, which will link downtown Minneapolis to Eden Prairie. Several said access to transit is critical for employees, customers and residents alike. The current route is close to several of the Twin Cities’ largest employers, including UnitedHealth Group, Supervalu and Cargill.

But the project has generated opposition, not just among some transit-averse outstate and suburban lawmakers, but with residents opposing the route through Minneapolis and the southwestern suburbs. Also, another tax on Minnesotans is distasteful to many Republicans.

Even at the roundtable, which appeared to be a transit pep rally, some questions surfaced on whether a sales tax for Southwest and other projects would burden businesses that think they’re already overtaxed in Minnesota.

“If you asked local businesses if they wanted to pay more sales taxes for LRT, most businesses would say no,” said Pat MulQueeny, president of the Eden Prairie Chamber of Commerce. “They’d say, ‘Use the money you have.’ It’s not like they don’t support LRT.”

Hennepin County Commissioner Peter McLaughlin said other cities with burgeoning public transportation systems, such as Salt Lake City, Dallas, Seattle and Portland, Ore., rely on a regional sales tax to help fund and maintain transit systems. “People need to belly up to the bar to make investment inroads” in transit, he said.

Last week, the Minnesota Chamber sent a letter to legislators stating it supports “efforts to build consensus for an additional metro funding source for metro area transit — recognizing that any new transit investment in the metro must allow for flexible use and be tied to documented efficiencies and reform in the delivery of services.”

Bentley Graves, the chamber’s director of health care and transportation policy, said the “efficiencies” involve reforms at the Met Council, whose members are not elected, but are gubernatorial appointees. The actual reforms haven’t been specified.