Millions of Americans will be able to sign up for health insurance under the health law next year, but many will struggle to get the coverage they need. 

Some states have begun waiving their state-run health insurance exchanges to allow people to buy health insurance online. 

But others have said they are not yet ready to launch. 

The Kaiser Family Foundation said the insurance marketplaces would be open to people from January 15, with the first enrollees expected in March. 

“States should start to offer coverage immediately and make it easy for people to get coverage,” said Sara Guggenheim, senior vice president for health policy at the Kaiser Family Foundations. 

Health insurance companies are already trying to expand access to the marketplaces. 

Last week, USAA, the country’s largest insurer, announced it would expand to 26 states. 

It said it would add at least 1 million new enrollees to the network in the first two years, but the plan is not yet in place. 

A number of states have said the health insurance plans available online must be pre-approved by the insurance regulator, the Department of Health and Human Services (HHS). 

On Monday, USBA said it was “currently reviewing the application process for a state-based health insurance exchange”. 

It did not provide details. 

However, the regulator said it could take up to 90 days to approve a health plan if it was approved for enrollees who are already enrolled in a state’s exchange. 

In Washington state, which is a state with a state health exchange, the health insurer has said it is working with state regulators to expand enrollees. 

Meanwhile, in Texas, a state that did not launch its own health insurance market, the state’s insurance regulator has announced that it will expand its enrollees into the market in the coming months. 

At least one insurance company, Anthem, is offering an insurance plan through the state exchange.

It said on Monday that it was reviewing its enrollee pool in the state, and that it expects to expand to the entire state by the end of January. 

Earlier this month, the US Department of Justice announced that the Department was working with insurers and state regulators on the implementation of the Affordable Health Care Act. 

 The US Department said it wanted states to “implement their own exchanges and to offer insurance to enrollees in their state or region as soon as possible”. 

“We want to make sure we get this right, so we’re moving forward to get this done and ready to open exchanges in a timely fashion,” HHS Secretary Sylvia Burwell said. Read more About the author: David Hickey is a senior researcher with the Kaiser Foundation and a senior fellow with the Urban Institute’s Health Policy Center.