Police detain a protester as climate change activists demonstrate during an Extinction Rebellion protest at the Waterloo Bridge in London, Britain April 15, 2019. Photo: Henry Nicholls/Reuters.

London - Police said they had detained 209 people by Tuesday evening as hundreds of Extinction Rebellion climate change activists blocked several main roads in central London for a second day.

Many of the arrests were made overnight at Waterloo Bridge for people breaching an order restricting the location of Monday's protests and for "obstruction of the highway," the Metropolitan Police said.

Extinction Rebellion plans two weeks of protests in Britain and 32 other nations.

"At this time, there is serious disruption to public transport, local businesses and Londoners wishing to go about their daily business," the police said.

They said some 500,000 people were affected by the closure of 56 bus routes, adding that they "expect demonstrations to continue throughout the coming weeks."

"We have officers out on the ground engaging with protesters and local communities to ensure proportionate policing plans are in place," Chief Superintendent Colin Wingrove said.

"We need to ensure we are striking the right balance between allowing the right to a peaceful protest, while ensuring disruption to communities is kept to a minimum."

The police said those arrested included five people detained on suspicion of criminal damage in south London's Lambeth area, where protesters vandalized oil giant Shell's office, spraying slogans including "climate criminals" on the front of the building.

Activists parked a trailer with a pink boat bearing the message "Tell the truth" at Oxford Circus, one of London's busiest shopping areas, on Monday.

They blocked nearby Marble Arch and Waterloo Bridge to traffic in the "Shut down London" protest.

Some activists blocked carriageways with plants, sculptures, tents and other objects.

The boat remained in place, and the Marble Arch and Waterloo protests continued on Tuesday.

The police issued an order banning the protesters from Oxford Street, after an earlier order for the bridge, but allowed them to continue at Marble Arch.

Gail Bradbrook, one of the organizers, told broadcaster ITV that the the group wants to "get people to have a conversation" about the impact of climate change.

Bradbrook quoted renowned broadcaster and wildlife presenter David Attenborough's warning to a UN climate change summit in December, which is a campaign slogan for Extinction Rebellion.

"If we don't take action, the collapse of our civilisations and the extinction of much of the natural world is on the horizon," Attenborough said.

Extinction Rebellion held similar small protests on Monday in cities including Berlin, Heidelberg, Brussels, Lausanne, Edinburgh, Madrid, Denver and Melbourne.

US actor Willem Dafoe, British actress Emma Thompson, US philosopher and left-wing activist Noam Chomsky, and Canadian "No Logo" author Naomi Klein are among the high-profile supporters of the group.

Launched last year by several environmental groups, Extinction Rebellion, also known as XR, wants governments to "tell the truth about the climate and wider ecological emergency [and] reverse inconsistent policies."

It has urged Britain and other nations to enact legally binding policy measures to reduce carbon emissions to net zero by 2025, and set up a national citizen's assembly to oversee changes in environmental policy.