WASHINGTON – AARP lobbied for the new health care law and now it stands to profit, Republican lawmakers charged Wednesday as they called for the IRS to investigate whether the powerful interest group representing millions of older Americans should be stripped of its federal tax exemption.

Three veteran GOP representatives released a report that estimates the seniors lobby could make an additional $1 billion over 10 years on health insurance plans whose sales are expected to pick up under the new law. They also questioned seven-figure compensation for some AARP executives.

“Based on the available evidence, substantial questions remain about whether AARP should maintain its tax-exempt status,” said the report, released by Reps. Wally Herger of California, Charles Boustany of Louisiana and Dave Reichert of Washington.

AARP said profit had nothing to do with its support for President Obama’s health care overhaul, which expands coverage to nearly all Americans, a goal the organization has long pursued.

“Our decision to support health care reform was in no way, shape or form influenced by revenue considerations,” said spokesman Jim Dau. Polls show that seniors are more likely to oppose the new law than younger people, partly because the coverage for the uninsured will be financed by slowing the growth of Medicare spending.

“We believe AARP operates in direct opposition to their senior membership,” Herger said at a Capitol Hill press conference.

The business side of the organization runs money-making enterprises. The most lucrative involves “branding” a series of health insurance plans for seniors and older adults with the AARP name, akin to the Good Housekeeping seal of approval.

The public policy side is a civic organization that acts as a watchdog over Social Security and Medicare, representing the interests of some 40 million members and consumers generally. Boards overseeing the business branch and the tax-exempt social policy side have overlapping directors.