A young German backpacker killed in a horror smash that claimed three lives had only just started her New Zealand holiday.

According to posts in German on the Backpacker Neuseeland Facebook page, Marina Liebl arrived in the country on Tuesday and was starting her New Zealand adventure in the south.

The 22-year-old headed straight to Queenstown before embarking on a trip that was expected to last into summer.

"I have now arrived in Queenstown. My first destination in New Zealand," she wrote on Thursday.

She also invited anyone in the southern resort town to join her exploring the area.

Just three days later her trip was brutally cut short when she was killed on the Dipton-Winton Highway late Sunday night when the car she was in collided with another.

Southland couple, Jesse Phillip Ariki Douglas Shortland and his Samantha Jayde Shortland, both 28, also died in the crash, leaving their two children orphaned.

The couple's children - 2-month-old Heath and 2-year-old Skylar - were flown to Kew Hospital in Invercargill. The toddler had moderate injuries and the baby suffered minor injuries.

Police today said the Serious Crash Unit was continuing to investigate the deadly smash.

Jesse and Samantha Shortland were driving back from Jesse's father's funeral in Hokitika the crash happened, near Ladbrook Rd, about 9.30pm on Sunday.

Police said yesterday the children were still being treated for non-life-threatening injuries and were being supported by family members.

Jesse and Samie Shortland were killed in a crash in Southland on Sunday night leaving their two children orphaned. Photo / Facebook