NSW Police say an urgent search launched for a father and his 10-year-old daughter, who became lost while snowboarding in Thredbo, has paid off, with the pair spotted shortly before sunset.

A spokesman said the duo were being assessed by paramedics, but had been rescued and were safe and well.

Earlier a race against darkness was launched to find the pair, who were separated from their snowboards and the group they were with.

NSW Ambulance were first alerted at 2:55pm on Monday afternoon.

A spokesperson said the pair had become lost in "deep but lightly packed snow".

He said rescue workers believed the man's phone was running low on battery.

A spokesman for Thredbo Resort said the pair were believed to have been snowboarding in back country outside the resort's boundaries.

A large cold front brought significant snowfall to many parts of south east Australia over the weekend.

More than a metre of snow has fallen in Thredbo over the past three days.