Minnesota Gov. Tim Walz, a potential vice presidential contender, has emerged among labor unions as a popular pick to join Kamala Harris on the Democratic ticket, four union officials and a political consultant told ABC News.

Walz, a former public school teacher and union member, has drawn support for his record of pro-labor legislation in a blue-leaning state and his potential appeal with voters in nearby Midwest battlegrounds Wisconsin and Michigan, they said.

Still, some added, labor unions lack a consensus choice in part because it is difficult to determine which candidate will deliver the best chance of a Democratic victory in the November election.

"People are high on Walz," Steve Rosenthal, president of political consulting firm The Organizing Group, who has spoken with unions about the potential vice presidential nominee, told ABC News. "People in the labor movement would be very comfortable with him."

However, Rosenthal added: "Mostly people understand the desperate need to win. It's not like there's somebody who's the union candidate and people have coalesced around that."

Walz has signed into law a series of measures viewed as pro-worker. Last year, Minnesota established paid sick and medical leave, banned non-compete agreements and expanded protections for Amazon warehouse workers. In May, Minnesota enacted a measure providing a raise for Uber and Lyft drivers while averting a threat made by those companies to stop doing business in the state.

Sara Nelson, president of the Association of Flight Attendants-CWA, told ABC News that she considers Walz one of two top candidates for the vice presidential nod.

"He got the workers from Uber involved before passing the bill to support workers rights in the gig economy," Nelson said. "That trust of workers and that understanding of the engagement of working people is absolutely something we're looking for."

In addition to Walz, Nelson said she backs Kentucky Gov. Andy Beshear as a potential VP pick, citing his willingness to walk the picket line in a red state and his legislative record on issues important to the working class such as an expansion of healthcare access.

"Those two should really rise to the top," Nelson said of Walz and Beshear, adding that she had communicated that view to the Harris campaign. "It makes a lot of sense to lean in harder on workers’ rights when the MAGA talking points are trying to say they’re for working people.”

Representatives for Walz and Beshear did not immediately respond to ABC News' requests for comment.

Labor unions, a key part of the Democratic coalition, issued a flurry of endorsements for Harris over the days following her entry into the race. Harris spoke on Thursday in Houston at the national convention of the American Federation of Teachers, a teachers’ union.

“One of the best ways to keep our nation moving forward is to give workers a voice -- to protect the freedom to organize,” Harris said.

A senior staff member at a private sector union that backs Harris, who has participated in labor discussions about the vice presidential pick, said enthusiasm about Walz among union officials has grown in recent days. The person requested that their name not be used due to the sensitivity surrounding the Harris campaign's selection of a vice president.

"Walz may not be as splashy as some of the other potential folks, but I think he will really relate with working class voters, especially in the states we need to win in November," the person said.

Rep. Pramila Jayapal, D-Wa., a labor ally, said on Thursday that she favors Walz for the vice presidential nomination due in large part to his record on worker issues.

"I like Governor Walz," Jayapal told CNN. "I want somebody that's super pro-labor, that really gets unions and can speak to a core constituency of ours."

To be sure, labor officials have not agreed upon a preferred candidate for the position, according to people familiar with the matter.

The Service Employees International Union, the largest private sector union, declined to respond to ABC News' request for comment on the vice presidential selection. The AFL-CIO, the largest labor organization, also declined to comment.

Concern emerged in recent days over the potential selection of Arizona Sen. Mark Kelly due to his previous unwillingness to back the PRO Act, a major labor reform measure. On Wednesday, Kelly said he would vote for the legislation if it came to the Senate floor. His comments were first reported by the Huffington Post.

A representative for Kelly declined to respond to a request for comment. In response to a previous request from ABC News, Kelly's office said the Arizona senator has robustly backed labor.

"Senator Kelly is the son of two union police officers and has been a strong supporter of workers throughout his time in the Senate," Kelly spokesperson Jacob Peters said.

Rosenthal, of The Organizing Group, said the shift in Kelly's position warded off a concerted opposition campaign from organized labor.

"Had Kelly not taken the position he did, there would be a significant amount of pushback from labor unions," Rosenthal said, later adding: "Overall, it's really about winning."

Jim McLaughlin, president of United Food and Commercial Workers Local 99, the largest private sector union in Arizona, praised Kelly in a post on X on Wednesday. "Unions in Arizona know [Kelly] for his commitment to the state and to our nation," McLaughlin said. "I respect Senator Kelly and am encouraged by the consideration he is being given by the [Kamala Harris] campaign.

At least one labor leader took issue with Kelly after his newfound support for the PRO Act. "If he changed his position on the PRO Act, he would've signed onto it," Transport Workers Union President John Samuelsen told ABC News on Thursday.

"I've heard talk about Walz from other union presidents," Samuelsen added. "And Tim Walz certainly sounds like a dream come true relative to Mark Kelly."

A labor leader, who has endorsed Harris, voiced praise for Walz's pro-labor legislative accomplishments and his potential appeal in the Midwest. At the same time, the person lauded Kelly as a skilled campaigner who would perform well as a running mate. The person requested that ABC News not use their name due to the sensitivity surrounding Harris's selection of a vice presidential nominee.

The decision should ultimately come down to which of vice presidential choices best helps Harris win the election, the person added. "It's hard to know," they said.