The complaint filed in King County Superior Court in Seattle marks the latest effort by the online powerhouse to crack down on fraud on its site. Online shoppers are increasingly reliant on consumer-generated reviews on everything on Uber rides to hotel rooms to buying iPhone cases on Amazon.
About 45 percent of consumers consider product reviews when weighing an online purchase, compared to 31 percent of consumers that consider product information, according to Forrester Research.
Amazon says the writers of the fake reviews are liable for breach of contract because they violated Amazon's terms of service.
In a statement Amazon said the complaint is not against Fiverr.Com but against individuals selling reviews and says the vast majority of the reviews on its site are authentic.
"The challenge of merchants soliciting illegitimate reviews is one that faces all marketplaces and online platforms," Fiverr said in a statement. "In fact, in our own marketplace we restrict reviews to only those who we can verify have actually purchased a service.