(Reuters) - One of the most highly contentious Obamacare programs, which calls on states to expand their publicly-funded healthcare for the poor, could see a second wave of participation by U.S. states later this year or early in 2015, according to state officials and independent analysts.

Following are states whose governor's offices or legislators have held talks with President Barack Obama's administration about possible options for extending healthcare coverage known as Medicaid to uninsured low-income residents.

Also included are the financial costs and benefits they could see over the coming decade by opting for expansion.

The Obama administration says it will cover 100 percent of the cost of expansion through 2016, and never less than 90 percent thereafter, a prospect that would mean billions of dollars in new federal funding for even sparsely populated states. But Republicans worry that the federal government's commitment could weaken over time, leaving states to foot some substantial Medicaid bills.

The Medicaid expansion is part of a broader reform under the law called Affordable Care Act, or Obamacare, which aims to reduce healthcare costs, now the highest in the world, make health insurance more affordable and limit the number of uninsured Americans.

Medicaid was created in the 1960s along with the federal program Medicare, which provides health coverage for the elderly. Most Medicaid coverage, jointly financed by federal and state money, has gone to narrowly defined groups including children, pregnant women and the severely disabled - a fact that has left millions of poor adults without healthcare until now.

The following data comes from a report by the nonpartisan Urban Institute. Estimates are in the billions of dollars.

State State Costs New Federal Funding

Indiana $1.099 $17.3

Missouri 1.573 17.8

Montana 0.194 2.1

North Carolina 3.075 39.6

South Dakota 0.157 2.1

Tennessee 1.715 22.5

Utah 0.364 5.3

Wyoming 0.118 1.4

Three other states, which have rejected the Medicaid expansion up to now, could be in a position to reverse course if their Republican governors lose reelection to Democratic challengers in the November election, analysts say.

They are:

States State Costs New Federal Funding

Florida $5.364 $66.1

Maine -0.570* 3.1

Wisconsin -0.248* 12.3

*Some states are shown with state Medicaid savings, indicated by a negative entry, based on expectations that adults will continue to receive Medicaid benefits under pre-Obamacare programs.

(Reporting by David Morgan; Editing by Tomasz Janowski)