Berlin's former Tempelhof Airport, a Cold War icon, has become its biggest green space, but a battle rages over its future, pitting developers against defenders of the slightly anarchic playground.

On Sunday, when Europeans elect their new Parliament, Berliners will also vote on a question that may be closer to their hearts - the fate of the vast park, now a symbol of competing visions of the city.

Tempelhof sits right in the middle of the German capital of 3.4 million. At 300 hectares, it is slightly smaller than New York's Central Park.

The site echoes Berlin's turbulent and troubled history. On its northwestern edge looms the huge semicircular former airport terminal, typical of the Nazis' architectural gigantism, built between 1936 and 1941.

Early in the Cold War, Tempelhof became the hub for the Berlin Airlift, when Allied planes made about 277,000 landings in Berlin to supply the western part of the war-ravaged city with food and fuel during the Soviet blockade of 1948 and 1949.

Opened as a park in 2010, Tempelhof became a temple of outdoor recreation. In summer, the open sky is filled with kites, and people run, skate and cycle on the old runways, or simply sunbathe or enjoy a barbecue in the grass.

Rampant gentrification

Communal organic vegetable patches and herb gardens have sprung up, alongside bicycle workshops and other oddball do-it-yourself ventures, one of the latest being a miniature golf course made from recycled objects.

Now the area is a flashpoint in a debate about the development of Berlin, which has long been popular for its relaxed and affordable lifestyle but, according to some, risks losing its soul amid a building boom and rising rents.

The city plan that so angers opponents would build about 4,700 apartments, homes and commercial spaces, as well as a large public library, sports fields and a lake, that between them would cover about 20 percent of the field.

A citizens' initiative called "100 percent Tempelhof Feld" sprang up in nearby neighborhoods, its members fundamentally opposed to what they see as Berlin's rampant gentrification.

They collected more than 185,000 signatures, about 10,000 more than required, to launch Sunday's referendum.

"This development is not for the majority of Berliners, it's a project for investors," said Kerstin Meyer, a board member of the protest group.

Half of the buildings will be for businesses or priced out of reach of "two-thirds of the population of Berlin", charges the citizens' initiative.

On the other side of the debate, Gerhard Steindorf, director of the city's Project Tempelhof development, said the project aims to "preserve the diversity that characterizes Berlin".

Flats for newcomers

"All segments of the population must be able to live there," he said, with half the units to be rented out at affordable prices to middle-income families, rather than as luxury apartments.

In addition, he said, a green central core of "230 hectares must remain free in the middle, which is larger than the Tiergarten", Berlin's great park, west of the Brandenburg Gate.

He charged that the position of the citizens' initiative is "fantastical" and amounts to the dogma that "we should never touch it".

The city government argues that it must cope with an expected influx of people to Berlin - "250,000 to 285,000 by 2030", Steindorf said - and ensure they are not pushed to the distant periphery of the sprawling city.

Promoters and opponents of the Tempelhof development adamantly defend their respective points of view, but they agree on one thing -the outcome of the referendum is wide open.

Opponents were emboldened by a survey released on Friday by the Infratest Dimap institute, which found 54 percent were against the property development compared with 39 percent in favor.

Agence France-Presse