Liz Truss was interrupted by campaigners as she tried to deliver her opening speech at a Conservative Party in Eastbourne.
Green New Deal Rising protesters chanted “shame on you” and “Green New Deal” as they stood holding placards inside the venue.
“I believe we have some infiltrators and I will wait until they are dislodged,” said Mrs. Truss, stopping her speech.
Tory members of the audience could be heard chanting “out, out, out!”
Politics Hub: Liz Truss acknowledges ‘tough winter’ and Sunak under fire
After five people were removed by security personnel, he continued: “I can say a few words about the militants who are trying to disrupt our country and who are trying to disrupt our democratic process and are trying to disrupt our essential services.
“I would legislate immediately to make sure we stand up to the militant unions that keep common travelers from getting to work. And I would legislate to protect our essential services.”
The Foreign Secretary added: “And I will make sure that militant activists like Extinction Rebellion are not able to disrupt ordinary people who work hard and do the right thing and go to work.
“I will never, ever allow our democracy to be disrupted by unjust protests.”
Ms Truss was later interrupted at the tills by a protester for a second time.
“I can say I take it as a compliment that I’m so popular with Extinction Rebellion,” joked the Foreign Secretary.
Green New Deal Rising is described as a movement of 16-35-year-olds who are disrupting politicians to protest the climate and economic crisis and demand a Green New Deal – a ten-year plan to create millions of good jobs green work and restructure the economy.
Speaking to Sky News, one of the protesters who was kicked out, Fatima Ibrahim, said those in the room were “angry”.
“We are angry young people who have seen these boxes and we are tired of candidates who avoid the real crisis and the only answer they give is tax breaks for their rich cronies and the likes of BP and Shell while the rest of us are told to tighten belt us,” he said.
“As a movement, we will challenge whoever is prime minister.”
He added that Mrs Truss has “no credible plan” to deal with the energy crisis.
A press release issued by Green New Deal said the five activists stood up and interrupted Ms Truss during her opening speech to protest against rising energy bills and the climate crisis.
The group said they are acting in a week when energy companies BP, Shell and Centrica announced record profits and when British household energy bills are soaring.