Police have warned Extinction Rebellion organizers that they face arrest if they incite protesters to block roads around Parliament Square.
The Metropolitan Police said he was pre-empting and restricting himself to the situation.
Protesters must clear the area by midnight, police said, and may not gather in the Old Palace Yard, a site the group has demanded as a permanent protest camp.
In Parliament Square on Tuesday morning in small crowd of Extinction Rebell Protesters in Review
Amber, 23, who did not give her surname, said she was hopeful to change her position on the climate emergency.
"We just want to be heard … we have a lot of jobs, we just need some engagement from the government. They were on holiday, I know they were back and want to engage properly, but I'm not hopeful. "
The main protest of several hundred people arrived in Parliament Square just before midday, flags flying and drums beating.
Clarissa Carlyon from London said: "We are coming into Parliament Square because we have captured the media attention and attention to the globe, and now it's time for the politicians to talk to us."
More than 1,000 people have been arrested in the past week in a campaign of non-violent direct action orchestrated by the group
Most orders have been arrested for breaching. But Wednesdays order is the first to explicitly mention that organisers could be targeted for arrest.
A statement circulated to the media said: "Any organizer or person taking part in the protesting to comply with these conditions or not.
Over the bank holiday weekend it took a mass police operation to clear Oxford Circus, Waterloo Bridge and Parliament Square of the small protest festivals, which included stages, sound systems, workshops, wellbeing tents and free food.
Activists at each location had formed the barricades, securing themselves across roads and to key pieces of infrastructure using lock-on devices and superglue.
Also on Monday night, the police seized a powerful sound system from activists at Marble Arch, which was used to stage a performance by the dance music group Massive Attack on Easter Sunday.