The fumarole in Rotorua, which spewed mud the size of bowling balls, is not likely to endanger the public, the Rotorua Lakes Council reassured today.

A fissure opened up on a chine overlooking the famous Whakarewarewa village yesterday and has not abated.

But the risk of it widening or expanding from its present site at the northern end of the Meade Street cul-de-sac appears minimal.

Council's geothermal inspector Peter Brownbridge says the council had taken necessary precautions to ensure public safety.

This include barriers from Meade Street, which overlooked the village.

From the village side of the blow out, the latest fissure looks spectacular as it intermittently gushed mud balls and emitted steam offering onlookers and overseas tourists the best free show in town.

The occupants of 12 Meade Street, adjacent the blowout, have shifted premises temporarily to live with relatives.

Peter says they have two young children.

Peter Brownbridge at today's press conference.

A woman occupant living in the house first noticed the subterranean burps and 'venting undergound”.

Boiling mud was subsequently ejected from the opening – around the length of two cricket pitches – and it was reported to the authorities.

The 'venting' had continued.

A fault line runs along the bank, says Peter.

'Every now and then we get a flow of heat from the south – the village direction – and works its way along the fault line and comes to the surface.”

Normally, it was heat in steam, he says.

'This event is a bit unusual in that we have the ejector being thrown out and it's a lot worse than normal.”

The council is letting Rotorua's latest fissure take its course.

Peter's confident it presents no danger to the public.

During a descent on the stairway to a flat area the venue of the press conference today, Peter pointed to a strategically dug hole in the ground, from which wisps of vapour were emitting.

The hole had not changed its shape, indicating the latest burst alongside had not deteriorated.

The area is fenced off because the risk of ground collapses was 'quite high at the moment”.

A measured hole alongside is used as a marker for signs of further activity.

In the immediate term, there was no risk the 12 Meade Street house was in permanent danger. Nor was there concern of danger to other houses in the area.

A shed was in danger of collapse, however, because of ground movement.

'In my time with the council, this is the fifth time heat steam has worked in this direction,” Peter says, adding there was little danger.

'Historically, as far as I know, there hasn't been any adverse effects in the village itself. I don't see that this is going to be any different.”

A recent earthquake, nor a buildup because of the controversial closure of bores in the 1980s, did not seem a cause for the latest fissure.

Immediate dangers were ground collapse on the lip of the bank, the seat of the blow out.

Peter says one of the characteristics of 'these events” is that they happen very quickly and just as quickly die away.

Rotorua mayor Steve Chadwick says the council will take a high-level safety approach to the public and tourists.

'So, please don't come down here and cross this boundary.”

Rotorua Mayor Steve Chadwick underlines public safety.