Strange white light

Ohk so I live in a rural area of wellington NZ and was driving home from town through the countryside around 5.30pm. I was coming around a bend when the hill to my right lit up with a bright white light, then the light suddenly ceased. As i came around the corner i looked across the hills to see wtf was going on and a strong white light appeared about 100-200m above the hill. It was so bright it made me squint then within 2 seconds max it was gone.
The really weird thing is that it wasn't moving. It appeared and spread out widely from one point, then almost immediately retracted back to that point.

It wasn't the sun, it was pretty dark and the sun was in the west.
Wasn't a plane (light was far to strong)
Wasn't a spotlight, the light covered to great an area.
Also there are no houses around where i saw it

Does anybody have any idea what I saw??