HARRISBURG — With just six weeks until the presidential election, a judge raised the possibility Tuesday that he would move to block Pennsylvania’s controversial voter ID law.

“I’m giving you a heads-up,” Commonwealth Court Judge Robert E. Simpson Jr. told lawyers after a day’s testimony on whether the law is being implemented in ways that ensure no voters will be disenfranchised. “I think it’s a possibility there could be an injunction here.”

Simpson then asked lawyers on both sides to be prepared to return to court Thursday to present arguments on what such an injunction should look like. There is no hearing today because of Yom Kippur.

Simpson gave few if any further clues to what he may decide. But his comments provided a dramatic end to a day of testimony in a protracted and widely watched fight over the law, which requires voters to present photo identification at the polls.

Critics of the law have argued it is being rushed into effect — it was enacted in March — and will disenfranchise hundreds of thousands of voters, particularly minorities, the elderly and the poor. Democrats have branded it a thinly veiled attempt by Republicans to suppress the vote for President Barack Obama on Nov. 6 and boost Mitt Romney’s chances of winning Pennsylvania’s 20 electoral votes.

State officials have countered in public statements and again in testimony Tuesday that they have mounted an aggressive campaign of TV ads, mass mailings and other measures to educate voters about the law and provide free photo IDs to all who need them.

Simpson previously rejected civil-rights groups’ contentions the law put too many burdens on voters. But on appeal, the state Supreme Court sent the case back to him this month.

The high court instructed him to evaluate officials’ efforts to provide the required photo ID cards and decide whether the state was providing the “liberal access” to those cards the Legislature indicated when it passed the law.

In their 4-2 decision, the justices said Commonwealth Court was obliged to issue a preliminary injunction if it was not “convinced in its predictive judgment that there will be no voter disenfranchisement” resulting from the law. That decision paved the way for this week’s hearings.

Lawyers fighting the law said they would ask Simpson on Thursday to block it from taking effect until there can be a full trial on its merits.

“The only proper course here is to enjoin the law,” said David Gersch, one of the attorneys for individual plaintiffs as well as civil-rights and civic groups such as the NAACP and League of Women Voters.

Alfred Putnam Jr., representing the administration of Gov. Tom Corbett, countered that officials had done all they could to ensure every voter who needed a photo ID card can get one.

The latest effort was a step that was announced Tuesday in court to again relax requirements for residents seeking one of the state-issued photo IDs.

“The question raised is, is it too hard to get?” Putnam said in court of the voter ID cards. “And the answer is, it is not too hard to get.”

Under the new plan, which went into effect immediately, all voters will be able to apply for the voting-only picture ID by making one trip to a Department of Transportation licensing center, PennDOT Deputy Secretary Kurt Myers said at the hearing as he detailed the new plan. He said the plan was implemented to address justices’ concerns about possible voter disenfranchisement.

Myers testified voters will now be able to go to a PennDOT licensing center and apply for a voting-only ID without first having to apply for the state’s non-driver ID, with its more stringent proof-of-identity requirements. Applicants also will no longer have to show proof of residence, though they will still be required to give their Social Security number.