SPRINGFIELD, Ill. – Illinois lawmakers called Thursday for Gov. Rod Blagojevich to take quick action on a $1 billion relief plan for the state’s electricity customers, but the governor plans to take his time reviewing it.

Blagojevich might even decide to reopen the legislation and try to improve it, said Marty Cohen, his director of consumer affairs.

“If there are ways to improve it, we’re sure going to try,” Cohen said at a news conference. “We’re not ruling anything out.”

He called the size of the rebates “underwhelming.”

It took months to negotiate the version that lawmakers passed last week. Revising the package could lead to more lengthy negotiations with an uncertain outcome.

“We encourage the governor to sign this bill as is. We think it’s the right bill at the right time,” said Ameren spokesman Shelley Epstein. “If this gets delayed, it’s going to delay the relief we can provide.”

Lawmakers and Attorney General Lisa Madigan said Friday is a key day for the legislation. After that, an Ameren long-term contract to buy energy at fixed prices will expire.

The contract helps guard against sudden price spikes that would be passed along to consumers. If it expires and Ameren must seek a new deal, the cost to customers could be higher.

“If the governor does not sign that legislation today, he jeopardizes the ability to enter into those long-term contracts which provide substantial relief to the people of Illinois,” said Rep. John Bradley, D-Marion.

“Allowing the Ameren contract to expire puts the entire legislative package at risk,” said Madigan spokeswoman Robyn Ziegler.

Cohen disagreed.

“This bill has many complicated elements and we intend to review them all. There is nothing magic about any particular date,” he said. “There is no harm that comes to consumers, none whatsoever, from the governor taking the full and appropriate time to review this matter.”

The relief plan would roll back some of the increased prices that took effect in January, when a 10-year freeze on rates ended. Customers would get rebate checks and bill credits that would roughly cut the increases in half.

But prices would still be higher than last year, and they could increase in the future. A new state agency would be created to try to prevent dramatic rate surges.

Blagojevich was not involved in negotiating the relief package, leaving it to lawmakers and the attorney general.

Senate President Emil Jones, D-Chicago, joined in the call Thursday for Blagojevich to sign the plan.