Pressure is growing to reschedule the $90 million national Census within the year - but at a crunch meeting tomorrow, Statistics NZ's board will consider whether it can actually go ahead at all.

Census data is critical to almost every form of government and business planning from the economy, training early chidcare teachers to reinforcing pavements for mobility scooters for the elderly.

About two million Census forms had already been delivered, door-to-door, when the Christchurch quake hit on February 22. As well as displacing thousands of people, making it almost impossible to conduct a Census among them, it also damaged the statistics department's national processing centre in the city.

Nearly half of the $90 million Census budget has already been spent, including $12.7 million to contract Census collectors - who were paid in full for their services up until March 27, despite not having to finish the job.

Statistics Minister Maurice Williamson made the decision to cancel the Census this year; now he must consider a recommendation from Government statistician Geoff Bascand on when - or if - it can be rescheduled.

Usually, the Census is conducted every five years. If the delay in conducting it extends beyond a year, experts say it will no longer be statistically valid to map trends.

Carol Slappenden, the department's general manager for the Census, said deferring the Census was one option before tomorrow's board meeting; so too was cancelling it.

The Auckland Council has told Statistics NZ it wants the Census done early next year.

New Zealand's largest city was changing rapidly and Census data was essential for keeping tabs on population increases and changes in demography, said the council's research manager, Grant Barnes.

"The longer it goes beyond the five-year reporting period, the less reliable are the models and projections."

Counting the world

The census date is enshrined in the Statistics Act, stating a Census must be held every five years. Governor-General Sir Anand Satyanand revoked the Census date on March 3, and Parliament has until the end of the year to amend the act.

The UK's Census is next weekend, but Cabinet Office Minister Francis Maude has called it an expensive way of measuring population, announcing it will probably be the country's last.

The Netherlands stopped Censuses after 1991 after complaints about invasion of privacy.