WASHINGTON (Reuters) - Vice President Joe Biden acknowledged on Wednesday that it will be hard to reach the target on the number of people signing up for health insurance by a looming March 31 deadline for Obamacare enrollment.

The Congressional Budget Office had originally forecast that 7 million people would sign up for insurance, many with help from subsidies provided under the Affordable Care Act, commonly called Obamacare.

But the program got off to a rough start in October when a website used to shop for insurance plans failed to work for almost two months. The nonpartisan CBO recently trimmed its enrollment forecast for 2014 to 6 million.

Biden, on his way to a Democratic National Committee fundraiser in Minneapolis, spoke with a small group of people in the city who are working to help others sign up for insurance, and thanked them for their work.

"We may not get to seven million, we may get to five or six, but that's a hell of a start," Biden said, according to a pool report of his meeting.

The Obama administration said last week that 3.3 million people have enrolled in private Obamacare health plans between October 1 and Feb 1.

The deadline for 2014 coverage is March 31, and the administration and allied groups are pushing to convince more uninsured people in big cities to sign up.

(Reporting by Roberta Rampton; Editing by Bernard Orr)