The Government may extend its deadline to meet air quality guidelines because cities and towns are cutting pollution too slowly.

Environment Minister Nick Smith has announced a review of rules requiring cities to clean up the air by 2013 because, he said, 10 cities and towns including Auckland and Christchurch were unlikely to meet the deadline.

Regional councils have until 2013 to bring levels of lung-problem-inducing particulate matter, or PM10, in the air to within voluntary World Health Organisation guidelines.

If they fail, they face a ban on granting and renewing industrial air pollution permits.

Dr Smith said the review would look at whether it was fair for industry to pay the penalty of cities failing to meet pollution limits when most air pollution came from home fires and vehicles.

Concerns had been raised at the job summit held in February to discuss the economic recession about the effect on industry if pollution permits were stopped, he said. "In a major city like Auckland [halting permits] would cut hundreds if not thousands of jobs."

But Green Party co-leader Russel Norman said the Government was undermining the credibility of national environmental standards just when it was promising to beef them up through its review of the Resource Management Act.

"If they weaken [air quality standards] now, why would anyone take national environmental standards seriously in the future?"

Dr Smith said the review would look at three ways of changing the 2005 standards: extending the 2013 deadline, changing the ban on air pollution permits, and/or allowing regions a more lenient limit for the number of times they could breach the standards.

Under current rules regions are allowed just one breach a year starting in 2013. In 2007, Auckland breached air-quality standards seven times.

In February, Environment Ministry spokesman Todd Krieble said Auckland was on track to meet its target by 2013. Yesterday, the ministry said 10 of the 40 "airsheds" - places monitored because air quality is likely to be poor- had been earmarked as unlikely to meet guidelines by 2013 but all had action plans, or proposed action plans, to meet the deadline.

Breathing air heavy with particulates is thought to be responsible for about 1100 premature deaths in urban areas each year, and to cost around $1 billion in illness and sick days.

The Ministry for the Environment estimates industry contributes up to 10 per cent of cities' winter PM10 - particles one-fifth of the diameter of human hair that are easily inhaled and absorbed into the lungs. The majority is from home fires.

In Auckland, 64 per cent of PM10 in winter - when air pollution is most likely to breach health standards - comes from home heating sources, but transport overtakes home fires in summer.

A technical advisory group has been set up to review air standards and will report to Dr Smith in October, with a final report to the Cabinet due in February 2010. The review could recommend new penalties or incentives for regional councils to meet targets.

New Zealand's air-quality standards are based on recommendations from the World Health Organisation.

In 2007, 42 per cent of airsheds complied with daily standards for levels of PM10 - up from 31 per cent in 2005.

The same year, for the first time since monitoring began a decade earlier, air quality in all five main centres - Auckland, Wellington, Hamilton, Christchurch and Dunedin - met national guidelines for the amount of air pollution over a year. An air-quality report for 2008 is due to be released towards the end of this year.