The group was protesting against the government's plan to expand drilling for oil and gas in the North Sea in an attempt to secure energy independence.
The move has been criticized as incongruent with the government's previous pledge of achieving net-zero carbon emissions by 2050.
How did Sunak respond to the protest action?
"We desperately need our prime minister to be a climate leader, not a climate arsonist," Greenpeace campaigner Philip Evans said.
"Just as wildfires and floods wreck homes and lives around the world, Sunak is committing to a massive expansion of oil and gas drilling."
But Sunak's office rejected the protesters' claims, saying: "We make no apology for taking the right approach to ensure our energy security, using the resources we have here at home so we are never reliant on aggressors like [Russian President Vladimir] Putin for our energy."
The burning of fossil fuels such as coal, oil and gas has been proven to be among the main drivers of climate change, the effects of which have been seen in the increasing and more intense droughts, heatwaves and other forms of extreme weather reported in previous years.
The UK public's uncertain response to climate change
"Sunak is even willing to peddle the old myth about new oil and gas helping ordinary people struggling with energy bills when he knows full well it's not true," Greenpeace's Evans said, rejecting arguments from the Conservative leader.
"More North Sea drilling will only benefit oil giants who stand to make even more billions from it, partly thanks to a giant loophole in Sunak's own windfall tax."
Thousands of people have joined environmental protests across the UK in recent years calling for the government to take more action to tackle climate change.
Some of these have been met with widespread condemnation as protesters block roads with a majority (68%) having an unfavorable opinion of the group Just Stop Oil while at the same time, a larger majority (82%) consider climate change an important issue, according to a recent survey by YouGov.
A slight majority of 42% — around a third of respondents had no strong opinion — also said they would oppose a ban on new oil and gas developments in the North Sea.