Some theorised it was a meteor, while others were convinced it was thunder.
One commenter said the bang sent two cats flying off the bed and sent the dogs into a flurry of barking.
MetService meteorologist Peter Little said it was more than likely thunder from a storm hovering just above Tauranga Harbour.
He said at 3.06am there were three lightning strikes, almost at the same exact time, causing one loud boom of thunder.
The storm, just to the west of Tauranga, then moved on and there was no more thunder.
"It shocked a lot of people out of bed and created some mystery because there was just the one bang. But it's not uncommon for thunderstorms," Mr Little said.