Police are being diverted from "core local duties" that keep London safe by the Extinction Rebellion protesters, Scotland Yard has said.
More than 500 people have been arrested since Monday, including three charged with gluing themselves to a train.
Police rest days have been cancelled over the bank holiday, as more than 1,000 officers are deployed in London.
Sajid Javid said the climate activists had "no right to cause misery" and the Met Police "must take a firm stance".
Officers have also been asked to work 12-hour shifts, while the Violent Crime Task Force has had leave cancelled.
"This will have implications in the weeks and months beyond this protest as officers take back leave and the cost of overtime," a Met Police spokesman said.Image copyright PA Image caption
British Transport Police said it "continues to deploy additional officers throughout the London rail network to deter and disrupt further protest activity".
Heathrow Airport said it was "working with the authorities" following threats protesters may try to disrupt flights over the Easter weekend.