Aurora fans have been treated to an unexpectedly bright display lighting up the skies, with photographers capturing the lights as far north as the Bay of Plenty.

The US government's Space Weather Prediction Centre says overnight Saturday into Sunday (New Zealand time) their instruments observed changes in the geomagnetic field up to level G4 on the scale  - enough to be seen from some populated areas.

One is the lowest and five is the highest level on the scale.

Photographers posted pictures of the colourful lights - which are often able to be recorded by cameras even when they can't be seen with the naked eye - as far north as Nelson, Wellington and Tauranga.

Belle managed to get some lucky shots of the Southern Lights from Springston, south of Christchurch shortly before 3am on Saturday, as she was up early for an airport trip.

Her children, aged six and four years old, loved seeing the colourful lights captured through the phone's camera, she says.

Nick Keizerwaard's shots over Lake Henry in Southland show the vibrant greens, pinks. Photo: Supplied/ Nick Keizerwaard.

Nick Keizerwaard watched the display from Lake Henry in Te Anau, both through his camera lens and without it.

"I don't think anyone was expecting it to pop off as big as it did. You could see early in the evening that there was a fair bit of power [and] colours visible by the naked eye; but things really spiked around 1.30am," says Nick.

"When it peaked early this morning, you could easily see the vibrant reds and pale greens ... it was a really pretty display."

Nick says learning to photograph aurora is challenging.

"Like trying to photograph a fast-moving target, you're constantly having to change/adjust your camera settings to capture the action; it's a fine balancing act ... but I enjoy the learning process."

Emma Jenkinson was also thrilled to capture the geomagnetic lights early on Saturday.

"Last night was a bit unexpected, I just happened to be heading home and noticed the glow. [The] camera showed up the colours," says Emma.

She snapped her shots at 2.30am in Halfmoon Bay on Rakiura - Stewart Island.

The US Space Weather Prediction Centre posted that while more geomagnetic activity was expected overnight into Sunday, it was only expected to reach G1 - not high enough for aurora hunters to get excited.

The pillars of light, looking south from Stewart Island's Halfmoon Bay. Photo: Supplied/ Emma Jenkinson.

Karoline Tuckey/RNZ