AUGUSTA — The number of Maine residents enrolled in the new health care marketplace is expected to grow substantially over the next couple of months, the top U.S. Department of Health and Human Services official for New England told Maine lawmakers and industry experts Monday.

Christine Hager said that the first part of the open enrollment, which began last month, is the time when people will view their options before finally deciding on a plan.

“This is largely a shopping period,” she told the Health Exchange Advisory panel, a group overseeing the rollout of the health care law in Maine. “And the numbers that we’re seeing are … very encouraging.”

About 271 Mainers picked plans on the marketplace, a key component of President Barack Obama’s health care law, in the first month of open enrollment, according to a federal report released last week. More than 3,500 Maine residents submitted applications on behalf of nearly 6,500 people, like themselves, their spouses and children.

The state has estimated that as many as 250,000 residents, including about 130,000 uninsured, could use the marketplace, also called an exchange.

The low enrollment numbers, technical problems with the exchange website and concerns over consumers seeing their current insurance plans canceled have come under fire since enrollment opened on the exchange last month.

Some insurance company representatives and those assisting Mainers with the exchange said Monday that the federal website seems to have dramatically improved in the last week.

Obama announced last week that he’ll give insurance carriers and states the option to keep offering consumers plans that would otherwise be canceled for another year.

Anthem Blue Cross Blue Shield is canceling plans for about 8,500 Mainers and replacing them with a different plan that complies with the new law. The Bureau of Insurance says it’s still discussing with the company if and how that will change in light of Obama’s announcement last week.

Affordable Care Act 101

We break down the ACA, what it does and what it requires you to do.

• Just the FAQs ma’am: Frequently asked questions and helpful answers
• An ACA Timeline: How health care coverage has evolved.
• Where to get assistance and more info: There are more sources of information and help understanding how the Affordable Care Act affects you.