A New Zealand woman is facing extradition after she and an Australian man were arrested for the murder of a toddler that took place more than 30 years ago. 

A 70-year-old New South Wales man and a 59-year-old woman who is now living in New Zealand have been arrested over the death of the two- year-old girl. 

The woman was arrested in Palmerston North yesterday and now faces being extradited to Australia. 

Inquiry head Detective Superintendent Danny Doherty had praised the efforts of detectives during the past two years. 

"These allegations were only brought to the attention of NSW Police in October 2019, and it is due to the tenacity and dedication of our officers that two individuals have now been charged," he said today. 

"The level of violence allegedly used upon this child is abhorrent and left a father without his daughter or knowledge of her death for 34 years." 

Detectives were told that the child was fatally assaulted by a woman known to her, in about July 1987. 

A woman had then allegedly helped to dispose of the child's remains. 

Detectives raided a house Porters Retreat, about 40km south of Oberon, and arrested a man. 

He has been with being an accessory after the fact to murder and misconduct with regard to corpses. 

The man was refused bail and is due to appear in Bathurst Local Court today.