Vic man admits starting fatal house fire

A truck driver has admitted to starting a fire that killed his estranged wife and her new partner as they tried to rescue a dog from their burning home.

Genine Ballantine and her boyfriend Steven White, both aged 44, were attempting to rescue their pet from the flames when they died in September 2013, according to documents tendered in court.

Ballantine had been in an on-and-off relationship with David John Campbell, 45, for 20 years before she moved into Mr White's Deer Park flat with him in January 2013.

On Tuesday, Campbell pleaded guilty to two counts of arson causing death in the Melbourne Magistrates Court.

He and Mr White had been involved in an ongoing confrontation and both had extensive criminal histories, court documents say.

Campbell had visited the unit the couple shared with two other men on several other occasions.

Once he kicked in a window panel, another time smashing a kitchen window by throwing a hammer through it.

Early on September 20, 2013 he set fire to curtains through a window panel he had previously broken, police documents say.

Campbell told police he didn't intend to harm anyone and had lit the fire as payback to Mr White for hurting Ms Ballantine, according to court documents.

Mr White and Ms Ballantine's bodies were found in the public housing property the same morning.

Campbell will face the Victorian Supreme Court on Wednesday for a directions hearing.

Charges of criminal damage, reckless conduct endangering life and reckless conduct endangering serious injury with withdrawn.