Double murder accused Hakyung Lee's spending spree following her husband's death has been revealed in court

The 45-year-old's on trial in the High Court at Auckland charged with killing her two young children in 2018, whose bodies she hid in a storage unit for four years.

She's raised an insanity defence.

Police Forensic Accountant Andrew Yoon says the radical spike in spending included travel, female beauty and children's activities.

He says the latter stopped abruptly around the time of their deaths, but Lee continued to pay for the storage unit for years.

Her defence notes the spending wasn't at high end stores, saying she didn't live in luxury after her kids deaths.