The Christchurch earthquake has exacerbated a nationwide shortage of shipping containers with thousands in use as barriers around damaged buildings and unstable cliff faces, and as temporary storage for householders and businesses.

Using the containers as quake barriers was vindicated during yesterday's aftershocks, with motorists hearing boulders crashing into them as they drove down cliffside roads.

The self storage industry is also booming with heavy demand for units needed to accommodate furniture, personal effects and the overflow from businesses forced into smaller premises.

Royal Wolf hires out containers and since the February quake it has brought about 1000 extra containers into Canterbury, shipping them in from its branches around the country, as well as from China and Australia.

South Island sales manager Rick Mills says that following the economic down turn there has been a worldwide shortage of containers because shipping companies stopped buying new containers leading to the closure of Chinese factories that made them. Although the factories are up and running again, they are not back to full capacity.

Lack of shelf space in damaged Canterbury warehouses has had a knock-on effect, with warehouses further north running out of room for new stock, forcing them to hire containers for extra storage space.

Containers are in demand for other uses and Royal Wolf has provided the Fire Service with containers designed as accommodation units for the Australian mining industry. They are in use as sleeping quarters to replace damaged crew rooms at the Christchurch central fire station.

Mills says the company has just landed 45 containers fitted out for use as offices or shops complete with windows, wooden floors, heat pumps, power and data jacks.

Debbie and Wayne Hardaker are operating their Village Grape wine shop from a retail container behind their damaged Sumner premises. Wayne Hardaker says the weekly rental of $98 is much more affordable than Portacoms which are very hard to get. "We found one in Tauranga and it was going to cost $4000 to get it down her and $4000 to get it back."

Mills says demand for containers peaked in March but he expects another spike as house repairs get under way and as demolitios increase. "We're ringing around contractors to see what their immediate needs are to see if we need to bring in more from Australia.

Christchurch company YS Containers has more than 200 containers leased out and owner Noel Thomas says demand is unprecedented.

"Our Auckland supplier said if he had 1000 containers by Monday he'd be rid of them all by Friday...

In the last month we've had one customer who has hired about 10 to 12 40-foot containers because they've had to move out of a building in their complex.

Thomas has a waiting list of about 40 people wanting to buy containers and he says in some cases insurance companies are paying for the purchase because it is more economical than hiring containers for the two to three years it is going to take to rebuild houses.

Self storage units are another option for desperate home owners and businesses.

Safe Store has 1450 units in Christchurch spread over five sites and manager Fiona Paskell says the 60 units empty at the time of the February quake quickly filled up. "They went within a week or two and now we are full with about 20 to 30 people on the waiting list."

She says demand for shipping containers is high too and the company's lease stock of 200 is fully committed.

Storage Plus runs four self storage facilities in Christchurch and owner Dave Bailey is catering for a lot of CBD businesses in the red zone. "Sometimes they've been told 'you can get in today and only have an hour to get things out.'"

Bailey says he no longer hires out containers because the wide variations in day and night time temperature in Christchurch cause condensation which "rains" on contents .

"Unless the container has a proper pitched roof over it which eliminates most of that. If a container is sitting on its own it warms up nicely during the day then it cools off quickly at night, and that's very hard on furniture that's not made to have moisture anywhere near it. "