LYNN ? The federal Internal Revenue Service (IRS) is holding economic stimulus checks for dozens of North Shore residents who have yet to claim their share.More than 4,600 economic stimulus checks totaling over $2.6 remain unclaimed in Massachusetts, in addition to more than 1,700 regular refund checks totaling more than $1.7 million that were returned by the U.S. Postal Service due to mailing address errors.”We want Massachusetts taxpayers to get this money as soon as possible. If you think you’re missing a stimulus check or tax refund, take a few minutes to go on www.IRS.gov or call the toll free IRS stimulus or refund hotline at (866) 234-2942,” said IRS spokesperson Peggy Riley. “The Web site is open 24/7 to help you get your check.”According to Riley, all a taxpayer need do is update the home address once. The IRS will then send out all checks due, she said, noting that those taxpayers missing a stimulus payment should update their home address by Nov. 28 so that the checks can be reissued by the end of the year.Under the law, economic stimulus checks must be sent out by Dec. 31, 2008. These checks average $570. The regular Massachusetts refund checks returned to the IRS because they could not be delivered average $963.Taxpayers seeking information about a refund over the phone will be given instructions on how to update their addresses. Taxpayers can access a telephone version of “Where’s My Refund?” by calling (800) 829-1954.The IRS delivers most refund checks with no difficulty. Through September 2008, nationwide the government distributed 116 million economic stimulus payments with only about 279,000 checks undeliverable.Meanwhile, the IRS has distributed more than 105 million regular refunds this year with only about 104,000 being undeliverable, according to Riley.In both cases, well under 1 percent of refunds or stimulus checks were undeliverable, she said.