A 52-year-old man in the US state of Montana has denied a felony endangerment charge that alleges he infected an unknowing sexual partner with HIV.

The Billings Gazette reports Peter Northcutt, of Joliet, entered his plea on Wednesday before District Judge Blair Jones in Red Lodge, Montana.

The charge alleges he failed to disclose his medical condition to a man with whom he had a three-year sexual relationship, having met his ex-partner in 2005.

The man, referred to as T.V. in court records, later contracted HIV from the defendant, who has been HIV positive since 1997.

Mr Northcutt also faces trial on two counts of assault on a law enforcement officer and aggravated animal cruelty for a July 2011 shooting at his residence.

Prosecutors say Mr Northcutt shot at two officers sent to check on his welfare and then shot and killed 55 husky dogs on the property.