(Reuters) - A federal judge on Friday blocked a portion of a Wisconsin law that requires doctors who perform abortions to have admitting privileges at a hospital near their practice.

U.S. District Judge William Conley last month temporarily stopped the measure, days after Republican Governor Scott Walker signed it into law, and his latest ruling extends that indefinitely while a lawsuit proceeds against the provision.

Planned Parenthood, which filed the suit, is challenging the requirement that doctors performing an abortion have admitting privileges at a hospital within 30 miles of their practice.

The group, which sued in partnership with another abortion provider called Affiliated Medical Services, contends the law would create such hurdles for doctors that abortion in Wisconsin would only be available in the large cities of Madison and Milwaukee.

Conley, in his 44-page ruling, expressed similar concerns.

"Even if there were some evidence that the admitting privileges requirement would actually further women's health, any benefit is greatly outweighed by the burdens caused by increased travel, decreased access and, at least for some women, the denial of an in-state option for abortion services," Conley wrote in his opinion released on Friday.

A representative for Walker could not be reached for comment late on Friday, and the anti-abortion group Wisconsin Right to Life did not return calls.

"In Wisconsin, Texas, North Carolina and elsewhere we are seeing an unprecedented wave of attacks on women's health, and people are fed up with it," Planned Parenthood Federation of America president Cecile Richards said in a statement following Conley's ruling.

Earlier this week, North Carolina Governor Pat McCrory signed into law sweeping new restrictions on abortion clinics.

Texas Governor Rick Perry last month signed into law a similar statute as part of a sweeping measure that followed 12 other states in banning abortions at later than 20 weeks of pregnancy.

In previous rulings in Mississippi and Alabama, courts have blocked admitting privilege requirements for physicians who perform abortions.

Anti-abortion activists, frustrated at their failure to roll back the landmark 1973 U.S. Supreme Court decision that found women have a constitutional right to terminate pregnancy, have in recent years turned to enacting new abortion limits in states with Republican-controlled legislatures.

(This August 2 story has been corrected to remove reference to admitting privileges requirement which is not part of North Carolina law in paragraph 9)

(Reporting by Alex Dobuzinskis; Editing by Ken Wills)