* EU to attend pre-Rio New York talks next week

* Needs clear mandate on green economy goals

* Says EU needs to specific targets for Rio+20

By John Acher

HORSENS, Denmark, April 19 (Reuters) - EU ministers must back clear goals to clean up oceans, tackle water shortages and conserve resources if the 27-member bloc is to be a credible leader of global efforts to make the world more sustainable, the Danish EU presidency said on Thursday.

The Rio+20 sustainability summit to be held in June has already been criticised as far too vague to achieve meaningfulness results.

Danish Environment Minister Ida Auken said her fellow EU ministers had been reticent about moving towards "clear operational targets and concrete actions" on five areas. They are water, marine environment, land-use and biodiversity, sustainable energy, resource efficiency and waste management.

In particular, she said protection of the world's oceans was a new area, little touched upon by Europe's policymakers.

"We want targets saying that we want to halve the amount of litter that we throw into the oceans before 2025," Auken told Reuters at an informal meeting of European environment and energy ministers.

"This is, of course, a very ambitious target, but it is important that we really show that we are serious about setting some new standards in Rio," she said. "If we cannot do that, if we cannot become concrete, it will just be a semantic exercise."

European Environment Commissioner Janez Potocnik told a news conference that the targets, including for reducing waste in oceans, were what the EU calls "aspirational targets", meant to call the world's attention to the problem, but not binding.

Auken will travel to New York next week to present the EU's position at U.N. talks ahead of the Rio+20 summit.

"I see a danger that some of my colleagues are afraid of the EU leading the negotiations and showing the way by pointing to what we ourselves want to do at home and think should come out of this," Auken said.

"There are some countries that are unwilling or afraid that this will be counterproductive if we feed too specific things into New York," she said. "I completely disagree with them."

"I think we need to become specific. We need to explain what we mean when we talk about an inclusive green economy so that the Rio negotiations can move further because there is nobody else leading these negotiations," Auken said.

She told a news conference later on Thursday the EU ministers at informal talks had shown support for the EU presidency's views before the New York meetings.

She had urged a more decisive stance in a letter to EU ministers ahead of this week's meeting.

"The EU's credibility and leadership is dependent on our ability to be precise on what targets, actions and time frames we aim to achieve in Rio," the letter said.

The EU is also trying to draw up its own green road maps on a more sustainable future, which will be debated further at formal EU meetings with decision-making power. (Additional reporting by Barbara Lewis Editing by Maria Golovnina)

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