Media agency spend for March fell almost 5% year or year as election uncertainty hit business confidence.

Total bookings – excluding government bookings – fell 4.7% on a like-for-like basis to $583.6m.

SMI said it was the sixth consecutive month of lower demand.

Outdoor was the only sector to record a modest rise, up 2.4%. All other categories declined.

Uncertainty is affecting most advertisers, with three quarters of product categories pulling spend, said SMI. Food/produce/dairy spend is back 23% year-on-year, retail down 12%, and automotive spending 7.7% lower than a year ago.

The knock-on impact is that agency bookings for Q1 2019 is -4.2%, which SMI said was the largest decline since 2009, when markets were hit by the global financial crisis.

"The downturn in media investment is not going to start to pick up until after the election when hopefully the new Government will be able to restore business confidence and therefore inspire businesses to start reinvesting in advertising," said SMI AU/NZ managing director, Jane Ractliffe.

"The good news for major media is that SMI has always seen large upticks in advertising expenditure following periods of lower growth ... the only question is when that growth will start to kick in."