CUPERTINO, California (Reuters) - Apple Inc will donate sales of select apps in April to the World Wildlife Fund amid its growing focus on environmental issues, the company announced.

As part of Apps for Earth, launched Thursday, the iPhone maker and developers will donate proceeds from 27 apps created for the campaign to the conservation group.

The campaign, which will run through April 24 and is among the first of its kind to be delivered in the App Store, follows a slate of recent environmental efforts from Apple and reflects the more socially conscious image Apple CEO Tim Cook has cultivated for the company.

"We have been putting quite an emphasis these past few years on environmental initiatives at Apple, really trying to walk the walk with respect to our own operations and how we make and recycle our products," said Lisa Jackson, Apple's vice president of environment, policy and social initiatives. "This is about engaging our customers in our work."

Apple has come under fire in the past from environmental advocates who criticised the company for relying on suppliers who are heavy polluters and constructing its devices so tightly that their components can be difficult to disassemble, refurbish and reuse. But the company has spearheaded a variety of projects to clean up its operations at home and overseas, announcing plans last year to build 200 megawatts of solar energy projects in China.

Last month, the company unveiled a robotic system called Liam to take apart junked iPhones and recover valuable materials that can be recycled.

The partnership with developers allows Apple to raise awareness of environmental issues among the App Store's hundreds of millions of customers, said Carter Roberts, president and CEO of the World Wildlife Fund in the United States.

More work remains for Apple to green its operations. Amid concerns about waste from electronics in China, one of Apple's fastest growing markets, the company is working with the Chinese government on its collection program, Jackson said.

And the company joined with Google, Microsoft and Amazon earlier this month to a submit an amicus brief supporting the Environmental Protection Agency's Clean Power Plan, signalling that the iPhone maker may be more involved in federal policy going forward.

"I think you can expect Apple to stand up for its values everywhere we need to," said Jackson, who previously led the agency.