Borce Ristevski, 55, pleaded guilty on Wednesday to the manslaughter of his wife almost three years after she went missing in June 2016, hours before his trial for murder was due to begin.

The surprise admission came after years of him denying any involvement with her death.

Mrs Ristevski's aunt Patricia Gray told The Herald Sun on Friday it was too little, too late.

"He has done this for selfish reasons," she said.

"He is either covering up for someone or just can't face it. I don't know."

Back in July 2016, during a public appeal for information about Mrs Ristevski's disappearance, Ms Gray stood alongside Ristevski and the couple's daughter Sarah.

The press conference ended when Ristevski was repeatedly asked if he had killed his wife. He did not answer.

Ristevski was charged in December 2017 after a lengthy Victoria Police investigation that involved listening devices and the analysis of CCTV footage.

Ristevski was accused of killing his 47-year-old wife at their Avondale Heights home on June 29, 2016, and using her Mercedes-Benz roadster to dispose of the body in bushland.

Her skeletal remains were found between logs in Macedon Regional Park eight months later.

Ristevski will face a pre-sentence hearing on March 27.

Australian Associated Press