The grey concrete Athens cityscape is set to go a dramatic electric orange, blue and green makeover one-month before the opening ceremony of the Olympic Games.

Buildings, bridges and 370 kilometres of cement highways will be dressed in the same colours as the uniforms of thousands of Olympic volunteers, organisers said on Thursday.

"Like all Olympic cities Athens wants to look its best," said Games chief organiser Gianna Angelopoulos.

"We want all Greece dressed in Olympic colours... beyond the venues we will dress the roads, squares and bridges," she told reporters.

More than 65 per cent of the greater Athens area is cemented over and delays to infrastructure works have left little time to add greenery to the urban sprawl.

Instead, visitors will be confronted with multi-storey canvases bearing logos of the Olympics and sponsors.

Tens of thousands of metres of printed canvas along with 20,000 banners and 21 kilometres of multicoloured fencing will provide Games camouflage for the city's less scenic areas.

In eight rundown areas of the city entire buildings will be dressed in giant photographs of ancient Olympia or the country's trademark olive groves.

Elsewhere in town, bare cement facades will be transformed from eyesores into giant projector screens showing scenes from old and new movies shot in Greece.

Five themed main routes through the city will showcase the work of contemporary artists, featuring interactive installations and sound and light shows.

A dozen giant balloons will dominate the skyline marking out key walking routes for visitors.

The Games open on August 13.