"His car was brightly coloured - it was silver and the silver caught the corner of my eye."
He climbed down to find Mr Christie lying unconscious and "pretty badly beaten up" beside his vehicle, which had come to rest about 15m from a swollen river.
"He was totally unresponsive. I don't think he had much longer to last down there. It was quite cold and he'd been there most of the night I'd say. It had been raining on and off. He must've been a reasonably tough character."
Mr Westcott alerted emergency services about 10am and gave Mr Christie, who momentarily stopped breathing, basic first aid.
Police, fire and St John ambulance crews from Wairoa responded, along with the ECT rescue helicopter from Gisborne.
Mr Christie was transferred to Hamilton from Gisborne Hospital by a rescue helicopter before he died two days later.
The police serious crash unit is investigating Mr Christie's death.