The opening day's ended in the trial of the mother who allegedly murdered her three young daughters in Timaru.

South African born Lauren Dickason pleaded not guilty to killing her six-year-old daughter and two-year-old twins in September 2021.

The 41-year-old admits killing the children, but is mounting a defence of insanity.

NZ Herald senior reporter Anna Leask says the jury has to decide whether Dickason intended to kill them.

"The Crown is saying that when these children came along, the stress and pressure intensified on her so much- the fact that they were impacting on her relationship with her husband and that she's snapped and killed the children as a result."

Defence lawyer Kerryn Beaton told the court Dickason was a loving mother who went through 17 rounds of IVF.

LISTEN ABOVE