AUGUSTA — Community health centers and navigators across Maine were flooded with calls and in-person requests for help Monday as last-minute health insurance shoppers sought coverage before the end of federal health care law’s six-month enrollment period.

Advocates and assisters saw a surge of demand from those who want to buy health insurance and avoid the fines they could face under the Affordable Care Act if they don’t have coverage by April 1.

Cherri-Ann Parris, a certified application counselor who was holding walk-in hours Monday at Community Concepts in Lewiston, said she’s confident she and her two colleagues will be able to provide help to all those who seek it, but it will be a challenge.

“It has been really hectic and that’s totally fine, that’s why we’re here,” she said. “We’re really going full throttle toward the end of today just to get everyone that we can enrolled.”

Maine, one of the 36 states that opted to allow the federal government to run its exchange, is among the top-performing states for enrollment. More than 25,400 Maine residents picked health insurance plans by March 1, surpassing the target of 23,000 set by President Barack Obama’s administration for the entire enrollment period.

Jake Grindle, health services navigator for Western Maine Community Action, attributed the state’s success to the tight-knit health centers and nonprofit organizations that have been working furiously together on outreach, education and enrollment.

WMCA started running out of appointment slots over the last week but has been coordinating with the health centers and other organizations that have extra staff to ensure that people can find help, Grindle said.

Health care advocates thought the younger crowd would wait until the last minute to sign up, potentially boosting Maine’s enrollment figures in the 18-to-24 age bracket, which was at 19 percent compared to 39 percent for the 55-to-64 age bracket in March.

But Bjorn Streubel, a navigator with Waldo Community Action Partners, which is processing about eight to 10 applications a day, said the 20- and 30-year-old crowd has been “nonexistent” at his agency

“They are just not there,” he said. Most of the signups have been ages 50 and older, he said.

Advocates urged residents still seeking coverage to begin enrollment; if they start by midnight and don’t finish, they will be given extra time to complete the signup.

That means that the work for navigators won’t end at midnight. Bjorn said he expects they’ll continue booking appointments through at least April 10 to help people finish their applications.

“The important thing is that people get in line,” said Emily Brostek, consumer assistance program manager at Consumers for Affordable Health Care.