Behind the campaign are the site Skiftet and Black lives matter Sweden, which now wants to "influence the Liberals' future members of the Riksdag".
The moderates' party secretary Gunnar Strömmer announced on Friday that negotiations with the other right-wing parties are now underway.
The email bombing campaign against the Liberals aims to get L to "vote no to an SD-supported government", alternatively to make them "feel so much shame that they will never forget the day they gave way to the fascists", according to Skift's website.
"This with trying to threaten someone to decide what you want is a very bad method, I want to say hello," writes Romina Pourmokhtari (L) on Twitter.
She is on L's Riksdag list and was until recently chairman of the Liberala ungdomsförbundet.
Pourmokhtari informs SVT Nyheter that she has nothing more to add.
The Liberals' press service says they are aware that some of their top names received a large number of emails during the day, but cannot comment beyond that.
"Democratic Contact"
Robin Zachari, head of office at Skiftet, believes that the campaign is not about threatening anyone.
- It is about democratic contact with those in power.
It is ordinary citizens who get in touch with politicians and if you can't do that, you shouldn't work as a politician.
The liberals have thrown all their values under the bus and are ready to rule the country with the help of the Sweden Democrats.
We will organize a resistance and besides, L themselves are arguing internally about this.
The shift was previously called Alliansfritt Sweden, and claims on its website that it "does not receive money from political parties or government bodies".