Boris Johnson condemned environmental protesters who are “wreaking havoc” on the nation’s roads.
Downing Street said Just Stop Oil demonstrations were costing taxpayers millions of pounds and “putting lives in danger”.
Home Secretary Priti Patel has accused the “thugs and so-called eco-warriors” of “waging a war against the British people”.
No 10 said Mr Johnson backed her words, with a spokeswoman adding: “Obviously the right to protest is a fundamental principle of our democracy but these demonstrations are wreaking havoc on our roads and they’re disrupting thousands of journeys and costing millions in taxpayers’ money and also putting lives in danger.
“To date, Just Stop Oil protests have cost police and other agencies millions of pounds and police on the ground have made over 1,000 arrests to date of Just Stop Oil protesters who are distracting officers from preventing crime and keeping our communities safe.”
The Police, Crime, Sentencing and Courts Act increased the sentences available for offenders convicted of carrying out disruptive acts and police had more flexibility in the way that they manage protests, the spokeswoman said.
The Public Order Bill “will give police pre-emptive powers to prevent guerrilla tactics” and “we will continue to ensure the police have the powers that they need”.
Essex Police made eight arrests on Sunday night after protesters blocked an oil tanker in Essex.
Officers were called to the scene in St Clements Way in Grays at around 8pm on Sunday after reports of a group obstructing the road and a tanker.
One person climbed on top of the vehicle while others are reported to have deflated its tyres.
Just Stop Oil revealed last week that protesters had dug a tunnel underneath the carriageway – a key delivery route for a nearby oil terminal.
The group said its tunnellers “are still underground disrupting the oil death machine”.
