Paymark said a big contributor to the modest start this year was the softer Auckland housing market.
Auckland house sales have been fewer this year and dwelling consents growth slower.
"The softer housing market has transferred to slow annual spending growth amongst Auckland/Northland housing-related merchants in recent months," Paymark said.
Their annual spending growth rate through Paymark was 1.7 per cent in September and has averaged only 0.6 per cent in the past three months.
In the rest of the country, the housing-related merchants have fared better in total.
Their spending growth was 4.8 per cent in September, slightly higher than the average of 4.5 per cent for the past 3 months.
In other sectors, a noticeable change has been the rapid slowdown in payment growth through accommodation merchants since July - coinciding with the end of the Lions tour.
Annual growth for accommodation merchants was 2.1 per cent in September, down sharply from 8.2 per cent in July and an average 16.9 per cent annual growth rate in the 12 months to June.
Across all sectors, payments through Paymark in September were $4.81 billion.
The annual underlying spending growth rate was a moderate 4.5 per cent.
"The core retail sector maintained their recent trend growth while growth slowed in total amongst automotive and non-retail sector merchants," it said.
Seasonally adjusted, total underlying spending was unchanged between August and September.
For the quarter ended September, underlying spending increased 0.8 per cent, seasonally adjusted, similar to growth during the June quarter.
Both quarters grew slower than the 1.6 per cent averaged in the previous four quarters. It appears the combination of slower lending growth and higher rent and mortgage bills is continuing to constrain household spending generally at present.
The highest spending annual spending growth during September was in Wairarapa, with 9.4 per cent growth, followed by Hawke's Bay (9.0 per cent) and Marlborough (8.3 per cent).
The slowest regions were Southland (down 2.5 per cent), Nelson (up 1.5 per cent), West Coast (up 3 per cent) and Waikato (up 3.1 per cent).
Paymark covers more than 100,000 terminals, accounting for in excess of 75 per cent of the New Zealand payments system, processing around 60 transactions every second of the day. -- Staff Reporter