Green activists placed rows of boots and shoes in a Zurich square to take the place of protesters who normally come out in person on Fridays to demand action on climate change.

Organisers said they wanted to make their point while respecting curbs on public gatherings imposed to contain the novel coronavirus, which has killed more than 1,300 people in Switzerland.

"Let us show solidarity in every crisis, also towards those people who are already suffering from the consequences of the climate crisis," said Fiona Chiappori from Climate Strike Switzerland, part of the global Fridays for Future movement.

"We demand that every crisis is seen as such and treated appropriately."

The desert boots, trainers, multi-coloured flip flops and lace-up boots formed a large block in the city's Sechselaeutenplatz.

A handful of people stood in the background holding banners reading "Wake Up: Climate Action Now" and "Crisis is Crisis" before being dispersed by police without incident.

Greta Thunberg - the schoolgirl activist who founded the global Fridays for Future protest movement - acknowledged on Friday that demonstrators were having to change tactics.

"Today we had planned a global climate strike with millions taking part. But in an emergency you have to adapt and change your behaviour" she tweeted alongside a photo of a pair of shoes and a coat hanging on a railing next to a banner.

She told an Earth Day event on Wednesday that countries have a chance to choose a new path as they begin to return to normal after coronavirus lockdowns.

Last year was the hottest on record in Europe, according to a study released on Wednesday by the EU's Copernicus Climate Change Service.