MIRAA users and traders in Lamu have said they do not support the plan by the National Authority for Campaign against Alcohol and Drug Abuse to limit the hours of chewing the plant to five a day.
They said they do not see the reason for such a rule as the crop is a mild narcotic.
The traders said such a law will affect their business.
Nacada director Mohamed Fazul had in earlier media reports indicated that the body is in the process of drafting a law that seeks to regulate the use of miraa.
The agency proposes that miraa chewing be allowed from 5pm to10pm.
However, the traders said they are grappling with a security curfew between 6.30pm to 6.30 am which has "punched enough holes" in their business.
Lamu Miraa Traders Association chairman Nyiva Syombua said: "The security curfew has made us lose a lot of profit since the business does well in the evening. We can't sell miraa in the afternoon. That means we have to sell by 5.30pm and be through before the curfew kicks in."
He said he has had to throw away a good amount of the crop after it went bad since he would not sell it because of the curfew.
"The curfew has done my business its worst. Miraa is best chewed in the evenings. What Nacada wants to do is unfair.We can't have two curfews in place. That will kill us," Syombua said.