Congress should be paying more attention to the effects of insurer consolidation on health coverage rates, a benefits broker says.

The major reform bills now before Congress could make matters worse, rather better, by tightening the grip the biggest carriers have on the health insurance market, according to Samuel Fleet, president of AmWINS Group Benefits, Warwick, R.I., the benefits brokerage unit of AmWINS Group Inc., Charlotte, N.C.

Fleet argues that one of the most important forces shaping the health insurance market is the dominance of the for-profit Blue Cross and Blue Shield plans; UnitedHealth Group Inc., Minnetonka, Minn.; Aetna Inc., Hartford; and CIGNA Corp., Philadelphia.

Not one of the major health bills would reduce the health giants’ dominance, and some provisions might make the giants more powerful, Fleet says.

Under the current rules, “they are able to hold service providers hostage to lower and lower reimbursement rates, they generate larger and larger profits for themselves that are not passed on to consumers, and they protect turf by blocking entry for smaller firms,” Fleet says.

The big carriers may be negotiating steep discounts, but they then charge very high administration fees, Fleet says.

The government could help by setting procedure reimbursement rates at a fair cost for all plans, and using a federal antitrust law that protects small retailers to protect small health plans, to keep the big plans from using their size to push out smaller plans, Fleet says.