Convicted sex offender Stewart Murray Wilson has died.

The man infamously dubbed the Beast of Blenheim was most recently released from prison in August 2019 to live in his cottage on the grounds of Whanganui Prison.

Corrections operations director for the lower north region, Coralea Easther, confirmed to the Whanganui Chronicle that Wilson died in hospital on Monday morning.

"It appears he died of natural causes," she said.

"Next of kin has been notified, and registered victims are being advised."

In 1996 Wilson was convicted and sentenced to 21 years' imprisonment for drugging, assaulting and raping several women.

He was first released in 2012 to live in a cottage on the grounds of Whanganui Prison with an extended supervision order and the most stringent conditions ever imposed on a New Zealander.

Wilson was jailed again in 2018 after being found guilty of raping a woman, a then 9-year-old girl, and of attempting to rape a third woman during the 1970s and early 1980s.

Police had reinvestigated the sex offender in 2016, which led to the new charges.

- Jacob McSweeny, Whanganui Chronicle