Woman accused of stabbing former lover's wife and grandson to death with garden shears breaks down in court

A Chinese tourist accused of murdering her former lover's wife and grandson with garden shears sobbed hysterically in the dock as she was remanded in custody until July.

Cai Xia Liao, 45, is charged with two counts of murder over the stabbing deaths of Mai Mach, 69, and four-year-old Alistair Mach.

She didn't say anything during the short hearing before Chief Magistrate Peter Lauritsen in the Melbourne Magistrates Court today.

But her lawyer said Ms Liao, who is in Australia on a tourist visa, is on blood pressure medication and has suicidal thoughts.

This is her first time in custody.

In the court Mai Mach's daughter Amy Mach, supported by more than a dozen family members, carried an action figure and tiny framed photos of her four-year-old son.

Late on Wednesday night, after Ms Liao was charged with murder, Detective Leading Senior Constable Tony Harwood told an out-of-sessions court hearing that Ms Liao had allegedly bound and gagged Brian Mach, 61, first.

She then allegedly stabbed his grandson, Alistair Mach, in the head and neck while he lay in bed, before lying in wait for nearly ten hours and killing his wife Mai Mach in the backyard when she arrived home.

The court heard Mr Mach had recently ended a three-year relationship with the accused killer and the pair had gotten into an argument yesterday morning.

Ms Liao is also charged with intentionally causing injury, assault and false imprisonment to Giangwa "Brian" Mach.

She will return to court for a committal hearing in July.

With AAP.