A Rotorua woman says she thought it was an earthquake when a massive bubbling mud pool appeared in her Whakarewarewa backyard today.

"I got woken up about 2am thinking 'oh there's a huge earthquake happening here', there was a lot of shaking and jolting," Susan Gedye said.

She became unsettled when the shaking carried on for a while, and she went to check out her kitchen - where she saw what really was going on.

"I could see the steam all over the kitchen windows and then could really hear it, and so I looked out the kitchen window and just saw a big geyser coming out of the ground, from the pipe in the bank."

The big bangs were pretty violent, she said.

Ms Gedye was initially told she'd be safe since the pressure was coming out from above the bank and not underneath the house, and the experts would monitor it until the next morning.

"When the morning came ... it had turned into a huge mud geyser so that was kind of spectacular but different and a little bit scary."

As time went on, it become "tremendously" bigger, she said.

"Just as time has gone by - like hour or just every half-hour - it's turned into something really spectacular. It's like a huge big crater in the front lawn and there's mud flying like about 10 metres into the air."

She was then informed that there was a sinkhole under her kitchen, which could give way at any moment, and she would have to leave her house.

"That's the thing, it could stop in a minute, tomorrow or it could last two weeks, but the longer it carries on the worse the damage gets. The house won't be liveable again," Ms Gedye said.

She said steam had erupted there four times in the past 20 years.

"But it was just steam that would come out of the bank and it would last like for a few days or week or something and then just stop. This is the one that's going to do the damage that's going to be end of the property being lived in again."

She's now moved to her dad's house, and said the offers of support had been a source of comfort to her.