AUGUSTA – A wheelbarrow full of postcards from Mainers who oppose the sale of Verizon’s land lines to FairPoint Communications Inc. was delivered Tuesday to Gov. John Baldacci as state regulators prepared for their third public hearing on the proposal.

Groups opposing the sale delivered what they said were 5,000 cards in a wheelbarrow, plus more stacked in a wagon, which were signed by residents who were canvassed by activists.

At a State House news conference, critics questioned the North Carolina-based company’s financial capacity to maintain quality services while fulfilling promises to expand broadband Internet access in the largely rural region.

High-speed Internet access is increasingly important to businesses, health care providers, students and seniors, opponents said. Approval of the sale “could send Maine and its economy backwards,” warned Maine AFL-CIO President Edward Gorham.

The opponents spoke hours before the Maine Public Utilities Commission’s third hearing open to citizen comment on the proposed $2.7 billion deal. The Portland hearing followed earlier hearings in Fort Kent and Bangor. Additional sessions involving litigants in the case will be held.

Vermont’s Public Service Board conducted hearings earlier this month on the sale, and New Hampshire regulators will take up the case in late October. All three states’ regulators must approve the sale in order for it to stand.

A FairPoint official said the proposed sale drew support of large and small businesses, educational institutions and the tourism industry at earlier Maine hearings.

“We’ve been thrilled by the support we’ve been getting at these public hearings,” said Audrey Prior, FairPoint’s director of regulatory and legislative affairs. In response to Tuesday’s postcard delivery to Baldacci, Prior said, “We’re staying focused on the end game, and that’s approval.”

Baldacci said his administration, working with the state Public Advocate’s Office, “will oppose any deal that does not protect the interest of Maine ratepayers, taxpayers and workers.”

“At the same time, the Public Utilities Commission is examining the Verizon-FairPoint proposal, and we must allow this independent process to move forward. People must have confidence that the system for judging this deal is fair and thorough,” the governor said.

FairPoint has also said it plans to increase Internet access from 62 percent across the region now to 90 percent. It has also said it will create 675 new jobs.

But opponents of the sale are concerned about the prospects of a rate increase to cover costs of maintaining Verizon’s network. They question FairPoint’s ability to access outside support and equipment in the event of a disaster and say it will install relatively slow digital subscriber line, or DSL, service instead of the high-speed fiber network.

FairPoint has told Maine officials it intends to spend $16.1 million to expand broadband Internet service in the state.