Labour Party advocate Kieran McAnulty said that this was due to a larger increase in the cost of living as compared to wage increases in Wairarapa.
"The 2013 Census identified that since 2006 there has been a 20 per cent rise in median incomes in the Carterton district, a 19 per cent rise in South Wairarapa, 15 per cent in Masterton and only 9 per cent in Tararua.
"Sounds great," he said.
"But Treasury figures show that since 2006, the cost of living has increased 21 per cent during this period, showing that Wairarapa incomes have actually gone backwards in real terms."
"With the majority of Wairarapa businesses' turnover entirely dependent on people's ability to spend, as times get tight the whole region is affected."
Areas that have shown the greatest socio-economic improvement include Martinborough and Masterton Railway.
Councillor Max Stevens says there are a number of reasons for Martinborough's relative prosperity, including a high level of employment as compared to Northern Wairarapa.
"Martinborough is well served by the vineyards and the pool of workers comes from the neighbouring towns," he said.
"South Wairarapa's closeness to Wellington has a significant impact on our economic well being."
"It provides a source of both income and lifestyle for those who live here and commute over the hill, often with well-paid jobs."
"The other thing that is steadily happening is the migration of semi-retired and retired people, many financially comfortable in the South Wairarapa."
"Martinborough has experienced an influx of active 60-ish couples who enjoy and contribute to the town's community."