Labour has joined NZ First in calling for the Reserve Bank Act to be overhauled.
Finance spokesman Grant Robertson says its objectives need to be broadened beyond controlling inflation.
"That sole focus leaves the overall health of the economy exposed," he said today.
"In recent times we have seen an overvalued dollar and high interest rates hurt the prospects of our exporters, this week we have seen the trade deficit widen as exports have sharply declined."
Mr Robertson says controlling inflation is important but the narrowness of the bank's mandate must be addressed.
"For the past few years we have had low inflation but stubbornly high unemployment ... at the same time the Reserve Bank has not met the 2 percent midpoint of its inflation target since the current policy targets agreement was signed in 2012."
NZ First has argued for years that the bank should be allowed more flexibility when it sets monetary policy.
It has twice brought member's bills to parliament to achieve that - in 2012 and 2013 - but they were both defeated.
Leader Winston Peters says the bank should be able to promote growth and employment, and be able to boost the export sector.
Reserve Bank governor Graeme Wheeler is expected to leave the official cash rate unchanged on Thursday.