Employment jumped by 30,000 in the March quarter and the unemployment rate fell to 6.6 per cent, but the latest Household Labour Force Survey is softer than those headline figures would suggest.

It did not capture the impact of the February 22 earthquake. The earthquake occurred two-thirds of the way through the quarter's continuous survey and Statistics New Zealand suspended interviews in Christchurch for the rest of the period.

Two-thirds of the quarter's employment growth was in part-time jobs.

And two-thirds of the 39,000 increase in employment for the year ended March was in self-employed people, mainly women, rather than hiring by existing firms.

Given the high attrition rate among new businesses it questions how durable that employment growth will be.

The quarter's increase of 30,000, seasonally adjusted, in the demand for labour was met mainly by a steep rise of 28,000 in the labour force, rather than a reduction in the number of people unemployed - which fell 2000 to 155,000. To count as in the labour force someone has to be either working or actively seeking work.

The jump in the labour force pushed the participation rate to 68.7 per cent, its highest level since December 2008, but despite that the jobs growth was enough to trim the unemployment rate to 6.6 per cent from a revised 6.7 per cent in the December 2010 quarter.

"What's so tragic about a 6.6 per cent jobless rate anyway?" asked Bank of New Zealand economist Craig Ebert.

"A lot of countries would give their eye teeth for that sort of level, albeit we should hope for something a bit lower in due course. For a truly stuffed labour market, and economy, go back to the early 1990s, with 11.2 per cent [unemployment]."

Ebert said in the current context 6.6 per cent arguably represented a good result, "a soft landing, if you like, from the artificially low rates of unemployment we were vainly trying to sustain amid the previously overheated and imbalanced economy".

When Canterbury is excluded from the national figures the unemployment rate is slightly higher - 6.7 per cent, down from 6.8 per cent - but the quarter's employment growth is stronger at 34,000 or 1.8 per cent. Excluding Canterbury, the number of hours worked in the quarter rose 1.4 per cent, in line with the increase in employment, but when Canterbury is included hours worked fell 0.9 per cent - and they were responses gathered before the February quake.

ASB economist Jane Turner said that difference suggested many in Canterbury had had their hours substantially cut back or were still not working at all - although technically still employed - as a result of the earlier earthquake in September. The unemployment rate has saw-toothed over the past 18 months, with rises followed by falls, around a flat trend line of 6.6 per cent.

In light of this saw-tooth pattern, Deutsche Bank chief economist Darren Gibbs expects employment growth in the June quarter will be much weaker.

"Still, employment growth is close to 2 per cent in the year to March 2011 and the labour market is clearly improving, as evident in the fact the unemployment rate has declined from its recession high of 7 per cent [in December 2009] to its current 6.6 per cent."

The Reserve Bank in its official cash rate review last month said the economic outlook remained uncertain after the February earthquake.

"Given this uncertainty we believe the Reserve Bank is leaning towards being patient with regard to the monetary policy outlook until clearer trends present themselves," Goldman Sachs economist Philip Borkin said. "While it will note the strength in these figures, it is likely to want to see broader evidence of labour market improvement before it would consider altering its view of the outlook."

He expects the next change to the official cash rate to be a 50 basis point increase in the March quarter next year.