A toddler is dead after drowning at Waiwera Thermal Resort on the Hibiscus Coast this afternoon.

The 2 1/2-year-old girl had been at the pools with family group and might have entered one of the pools without being seen, police said.

According to a police statement, the alarm was raised at about 12.45pm by a person in the 1.6m pool, when lifeguards retrieved the toddler from the water.

Efforts to resuscitate her were unsuccessful.

The matter has been referred to the coroner.

The resort is about 35 minutes north of Auckland.

According to its website, it attracts more than 350,000 visitors each year.