AUGUSTA — Maine could become the next state to regulate ride-sharing companies such as Uber.

Secretary of State Matthew Dunlap said Friday his office has submitted legislation that would require ride-share drivers to register with the state and to prove that they have a valid driver’s license and insurance. Similar legislation has surfaced in several other states as San Francisco-based Uber Technologies continues its breakneck global expansion. The Silicon Valley-funded company posted investments worth $41 billion in early December. It began operating in Portland in October.

The Portland City Council is also considering a proposal to regulate Uber and other ride-sharing companies amid complaints from taxi companies that the services have an unfair advantage because they are not subject to licensing and insurance requirements.

The proposed Portland rules, along with regulatory efforts in other states, have also touched off an ideological debate.

Last year the Republican National Committee launched an online petition asserting that attempts to regulate Uber had been advanced by “taxi unions and liberal government bureaucrats” who are “setting up roadblocks, issuing strangling regulations and implementing unnecessary red tape to block Uber from doing business in their cities.”

Democratic lawmakers in other states have rejected the Republican characterization, arguing that supporting innovative companies such as Uber and ensuring passenger safety are not mutually exclusive goals. The company, suffering from a spate of public relations controversies, does not appear as willing to engage in the partisan battle. In August, it hired President Obama’s former campaign manager, David Plouffe, to oversee policy and strategy.

Dunlap, whose office oversees the Bureau of Motor Vehicles, said the legislation was a response to complaints – mostly from taxi companies – that Uber and other ride-share companies operate under a different set of rules. He said the proposal would be sponsored by Sen. Ronald Collins, R-Wells, the Senate chairman of the Transportation Committee, and is geared toward creating a regulatory framework to provide some public accountability for ride-share companies.

“It’s nothing really earth-shattering,” Dunlap said. “It’s basically to make sure that they (ride-share companies) do what everyone else … who does for-hire transportation of passengers has to do.”

Uber spokeswoman Kaitlin Durkosh said via email: “It’s encouraging that state officials are exploring a permanent home for Uber in Maine. We’re eager to work together on a modern regulatory framework that makes sense for ridesharing, and embraces the choice and opportunity it offers.”

Currently, Uber and similar companies are largely unregulated, although Durkosh said about 20 jurisdictions have created new rules to govern a service that is fundamentally different from taxi or limousine service. In many instances, Durkosh said, the new regulations simply codify existing Uber policies, such as liability insurance.

Uber passengers download a free app onto their smartphones. After entering credit card information, a passenger calls for a ride. A driver using his own vehicle accepts the request and initiates a tracking service that allows the passenger to monitor the vehicle’s progress in real time. The passenger can also monitor the route on the driver’s GPS. There’s no exchange of cash or tipping. The passenger’s credit card is billed for the fare and receipts can be sent via text message.

Uber drivers are independent contractors. The company keeps 20 percent of the agreed-upon fares, while the drivers receive the rest.

Uber has been in operation for five years. It was preceded by the rival company Lyft, which began in 2007 and operates in more than 68 U.S. cities. Uber has had an eye on global expansion. It has a low-cost subsidiary, UberX, and operates in 45 countries and 117 U.S. markets.

The expansion of ride-share companies in Europe has irked taxi unions there, resulting in sometimes violent protests. Taxi drivers in Europe are required to have professional taxi or chauffeur licenses, prompting some regulatory agencies to consider banning services such as Uber.

In the U.S., state and local officials have tried to strike a balance between ensuring the safety of passengers and regulations that don’t stymie innovative services popular with a public eager for alternative transportation options.

In June, Colorado became the first state to regulate ride-sharing services such as Uber. The sticking point was liability insurance. How much, if any, should ride-share companies have to protect passengers if their contracted drivers get in an accident? Lawmakers settled on primary commercial insurance coverage of $1 million. It covers the time between when the driver is summoned via the smartphone app and when the passenger is dropped off.

According to Uber’s website, the company already has the same level of liability insurance adopted by the Colorado law.

Other provisions in the Colorado law require drivers to be at least age 21 and have a valid driver’s license, vehicle registration and auto liability insurance. Drivers must submit to a criminal background check at hire and again every five years. The company is required to review the driver’s history. Some driving offenses, such as drunken driving, would prohibit a company from hiring the driver if the violations occurred during a set period of time.

The details of Dunlap’s proposal are not yet public. He said the bill will address liability concerns and require companies such as Uber to submit lists of their drivers. He said drivers would not have to have a commercial license to provide rides, only a Class C passenger license.

“Taxi drivers don’t have to have a commercial credential and we’re not asking for that for the ride-share drivers, either,” he said. “Taxi companies sort of set their own employment standards. Some do background checks. We’re not necessarily asking for that. It’s a very low threshold, really.”

Officials in Portland have also downplayed efforts to regulate ride-share services, arguing that the city proposal is designed to protect passengers and level the playing field with taxi and town-car services. Like other states, the dispute between Uber and taxicab companies is particularly acute at the Portland International Jetport. Uber drivers are allowed to pick up and drop off passengers in regular passenger lanes, whereas the city imposes a cap on how many taxicabs can operate at the airport. The taxicabs are chosen via a lottery system and must pick up passengers in the taxi pickup line.