About 20 activists have in recent weeks almost daily blocked off major roads in Stockholm's rush hour traffic.
Some have glued themselves to the roadway and the message is "restore the wetlands".
When the activists blocked the Liljeholmsbron in Stockholm last week, nine people were arrested on suspicion of sabotage.
The moderates now want to tighten the sabotage legislation so that the minimum sentence is increased from 14 days to 12 months in prison.
The party also wants to introduce mandatory detention for this type of action.
- The background is that we see activists almost daily who systematically block roads and make it difficult for thousands of people.
It is only a matter of time before an ambulance or police is blocked, says Johan Forssell (M), legal policy spokesman.
Mp critical
The Green Party believes that the Moderates' proposal is disproportionate and difficult to understand.
- Changing the penalty scale for some activists to take to the streets feels separate and more like a signal policy aimed at the environmental movement, says Martin Marmgren (MP), legal policy spokesperson.
Alfred Westh is one of the activists and he has participated in traffic jams on several occasions.
-We are in a huge climate emergency and ordinary people do not understand where we are going and therefore we have to sit down and disturb.
That politicians now want to punish us more severely is disgusting, he says.
SD: Change the law
The Sweden Democrats have previously launched a proposal similar to the Moderates', but whether there is sufficient support in the Riksdag for such a tightening of penalties is unclear.
- I hope there is a broad consensus because we can not have a state where this happens almost every day.
I urge the government to change the legislation otherwise we will do it after the election, says Johan Forssell.