Climate group Just Stop Oil said 51 of its supporters are disrupting seven petrol stations across London.
In some locations, activists rendered fuel pumps unusable by breaking their display glass or covering them with spray paint.
At others they blocked access by sitting on the road with banners.
The action started at around 6am
The Metropolitan Police said: “Protestors have targeted a number of petrol stations this morning, causing disruption and damaging pumps.
“Officers are at each of the targeted locations, we have made a number of arrests and specialist teams are removing those who are glued to pumps.”
The force earlier said it arrested four men and a woman on suspicion of criminal damage at a petrol station in Talgarth Road, Hammersmith.
Just Stop Oil has repeatedly protested against new oil projects in recent days, including at service stations on the M25 motorway.
Tez Burns, 34, a bicycle mechanic and physics graduate from Swansea taking action on Friday, said: “I can’t live with myself, knowing what I know, without doing all I can to stop new oil and gas.
“We are suffering the worst cost-of-living crisis in 40 years and facing climate breakdown because of our dependence on oil.
“Yet the Government is allowing energy companies to drive us into poverty with skyrocketing energy bills, and is failing to protect us from the consequences of climate collapse. Enough is enough.”