Only eight emergency call centre operators were on hand to receive 1000 calls for help in one hour on the day a torrent of water swept through Toowoomba, killing Donna Rice and her son Jordan.

The Queensland Police Union has come to the defence of the Toowoomba police officer who chastised Ms Rice when she first phoned triple-0 as water swirled around her car, saying regional call centres are under-resourced and under-staffed.

Jordan Rice, 13, drowned in Toowoomba after insisting his younger brother be rescued first.

The state floods inquiry heard yesterday that the Toowoomba emergency call centre is too small to accommodate an adequate number of staff.

In a triple-0 audio tape heard at the inquiry yesterday, it was revealed Senior Constable Jason Wheeler repeatedly castigated Ms Rice for driving along a flooded road on January 10 as she pleaded for help.