The acting head of Corrections says staff integrity is a priority, after revelations of a major prison corruption investigation.

Twenty people have been charged, including 15 Corrections and Reintegration officers at Auckland's Mt Eden, Waikato's Spring Hill, and Auckland South Corrections facilities - and five members of the public.

They're accused of smuggling phones, drugs and tobacco to prisoners in exchange for cash.

Corrections' acting chief executive Rachel Leota says they will continue to support staff.

"Work with our unions - and I met with them last night - there are many other things that we can be doing, and we will continue to commit to doing that to ensure our staff are safe." 

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