* DUH says excess emissions levels detected in 5 separate tests

* Renault has no immediate comment

* DUH calls for reform of European approval system

(Adds no comment from Renault, DUH quote, background on European testing and approval regime)

BERLIN, Nov 24 (Reuters) - Nitrogen oxide emissions of Renault's 1.6 dCi Espace were found in tests to be up to 25 times higher than the current Euro-6 limit, German environmental lobby group DUH said, as carmakers come under scrutiny in the wake of a scandal at VW.

DUH said on Tuesday excess emission levels for the Renault Espace diesel vehicle were detected under new European testing cycles (NEFZ) in five separate tests with a warm engine carried out by the University of Applied Sciences in Bern, Switzerland.

Renault representatives did not respond to calls and messages seeking immediate comment.

DUH called for a reform of Europe's system to approve vehicles, which has come under fire for giving that authority to national authorities suspected by critics of being too close to manufacturers.

"It is unbelievable that so-called modern diesel vehicles that damage the air we breathe in this way are on the road today," Axel Friedrich, co-founder of the International Council on Clean Transportation (ICCT), said in the DUH statement.

"This makes it clear that we will not advance with the current form of approval procedure but need a comprehensive reorganisation of the system, in which mandatory regular controls on the street are integrated."

The ICCT has called for tests to be carried out on vehicles in use rather than on cars specially prepared by manufacturers for testing purposes. It says they should take place in "real-world" conditions as well as in laboratories.

Volkswagen admitted in September to cheating U.S. diesel emissions tests, sparking a scandal that affects 11 million VW diesel vehicles worldwide, has forced out the company's chief executive and may cost billions of euros.

(Reporting by Andreas Cremer; Additional reporting by Laurence Frost in London; Writing by Georgina Prodhan; Editing by Maria Sheahan and Jason Neely) ((Andreas.Cremer@thomsonreuters.com; +49-30-2888-5084; Reuters Messaging: andreas.cremer.thomsonreuters.com@reuters.net))