Six people have been arrested after detectives investigating the supply of methylamphetamine and firearms searched properties across the Northern Rivers including in East Lismore.

"In February 2019, detectives from Richmond Police District established Strike Force Balsillie to investigate the supply of methylamphetamine and firearms in Casino," a NSW Police Media statement said.

"Following extensive inquiries, about 7am today, officers attached to Richmond Police District, along with officers from the Tactical Operations Unit, Northern Rivers Region Enforcement Squad, Operational Support Group and the Police Dog Unit executed 11 search warrants at properties in Casino, Drake, Tabulam, East Lismore, Lismore and Irvington.

"During these searches, methylamphetamine, cocaine, cannabis, cash, drug paraphernalia and firearms were located and seized.

"As a result, a 34-year-old woman and five men – aged between 32 and 49 – were arrested and taken to Casino and Lismore Police Stations.

"They are expected to be charged later today with a range of drug supply and firearms offences.

Richmond Police District Crime Manager Detective Chief Inspector Cameron Lindsay told media these arrests would cause a major disruption to local crime in Casino.

“These arrests today are the culmination of months of planning and investigative work conducted by detectives at Richmond Police District," he said.

“This will drastically reduce the drug trade in Casino, as well as other resulting crime.

“It’s an all of community effort to help find and catch those who are responsible for supplying these dangerous drugs on our streets – if you ever see anything suspicious, please report it to Crime Stoppers, remember you can remain anonymou."

Investigations under Strike Force Balsillie are continuing and further arrests are expected.