According to Social Development Ministry figures, 900 people were receiving the unemployment benefit in the Western Bay in March, up from 687 one year ago.
"Only when both sets of data show a sustained trend downwards can we feel totally confident in our employment situation," Mr Mason said.
The mixed results indicated "that for some the economy is improving and for some the opposite".
A breakdown of the labour force figures shows while employment and unemployment rates improved in the wider region, the total number of workers reduced.
Of the 119,500 Bay of Plenty residents aged 15 and over eligible for work, 110,000 were employed.
In the three months to December, the Bay of Plenty labour force stood at 120,800, with 110,400 people in jobs.
Nationally, unemployment fell to a three-year low for the first quarter of this year - 38,000 more people in jobs compared to the previous period.
The jobless rate was 6.2 per cent, down from a revised 6.8 per cent in the December quarter.
Despite this, 148,000 New Zealanders were still out of work in the three months to March.
Northland had the country's highest unemployment rate with 10 per cent of the region's eligible workers unemployed.
Council of Trade Unions said the drop in unemployment was encouraging, but more needed to be done for struggling Kiwis.
"There is no cause for satisfaction when there are [at least] 146,000 people unemployed and a further 83,300 part-time workers looking for extra hours," secretary Peter Conway said.
Despite this, Westpac Bank economist Dominick Stephens said the survey results "gave an unusually clear signal that the labour market has improved".
While much of the rebound was fuelled by high demand for workers in Canterbury, Mr Stephens said labour markets outside quake-affected Canterbury had also shown improvements.
Tertiary Education, Skills and Employment Minister Steven Joyce said the reduced unemployment rate reflected growth in the economy.
"While the fall in unemployment is a good result, it may be a little too good as this survey is known to move around and we need to be cautious." with NZ Herald
By the numbers
First three months of 2013:
8 per cent unemployment rate in the Bay of Plenty.
9500 Bay of Plenty residents unemployed.
119,500 residents aged 15 and over eligible for work - 110,000 employed.
