His comments come after a second guard at Upper Hutt's Rimutaka Prison has been charged with taking cannabis into the jail.
The 41-year-old man was charged on Monday and will appear in Wellington District Court tomorrow charged with supplying cannabis.
Police have said further charges were expected.
The guard was allegedly caught after information was intercepted through tapped prison phone lines during Operation Wire.
In June this year senior prison manager Jeffery Mark Reid, 43, three prisoners and two women were arrested and charged following a month-long cannabis investigation by the department.
Mr Matthews said he expected more arrests.
"I want to send a very strong message that, if any of our staff are engaged in this, we will come after them," he told The Press.
"They are clearly doing it for the money. It depends what the drugs are, but you might get $1000 for bringing them into the prison."
Drug-smuggling by guards was not a big problem, but a small minority were being tempted, he said.
Corrections Association president Beven Hanlon could not deny that some guards accepted money but said they were more often motivated by threats to their families.
Corrections Minister Judith Collins said yesterday she was confident Department of Corrections staff had "got the message" no corruption would be tolerated.
Ms Collins would not talk about a case that was before the court but said the department was working closely with police.
The public could have confidence allegations were being dealt with, she said.
"Any suggestion of corruption, any complaints that come to my office, which they do from time to time, goes immediately to the professional standards unit in Barry Matthews ' office and they are investigated -- and you can see the results of that."
