A controversial prediction of another big earthquake in Christchurch this weekend is causing families to leave the city in droves and has left children terrified.

Based on the moon and tides, weather forecaster and author Ken Ring has predicted another sizeable quake tomorrow, or close to it, and after the tragic events of February 22, many are not taking any chances and are packing up and leaving town for the weekend.

Mr Ring's claim has been roundly discredited by the mainstream science community, including the chief science adviser to the Prime Minister, Sir Peter Gluckman, who said: "There's no added risk of a quake on March 20 or any other day, and I think people do not realise the disharmony and the discomfort that is being given to a lot of people in the Christchurch regions by [predictions]."

Canterbury University geologist Mark Quigley has labelled Mr Ring's predictions "opportunistic and meaningless self-promotion during a time of national crisis".

Christchurch advertising consultant Kerry, 40, who asked her surname not be used, has fled the city for the weekend with her son Harry, 9, her mother, aunt and another solo mother and child.

As she drove south to Otago yesterday, she learned much of the accommodation south of Christchurch had been snapped up.

Although she considers herself a rational person and does not believe in Mr Ring's predictions, even the possibility of another quake was enough to make her get out of town.

"It does worry me. I think the guy is a complete fruit loop ... but whether he is right or not, he's really put the fear of God into everyone," Kerry said.

"Even though I might not believe in what he's saying, I'm still afraid of what he's saying. I'm scared enough to not be in Christchurch."

Kerry said her son had been picking up on the prediction through television and the internet, and it was worrying him.

"I don't think [children] completely understand but they are certainly very aware of how [Mr Ring] even named a date.

"It's bad enough for adults, let alone kids talking about it too."

The heavy media coverage of the prediction made it hard to ignore, she said.

Sir Peter said it was inevitable smaller quakes would rock the Christchurch region on a daily basis.

"Inevitably there will almost certainly be aftershocks of low magnitude in Canterbury on March 20 as there are today, tomorrow, and most days over the next two weeks," he said earlier this week.