Finance Minister Bill English is defending modest cost savings achieved so far from a drive by the Treasury to cut office support cost in the public service.
But Mr English says he expects public sector bosses to step up their efforts from now on.
The Treasury is sticking to its previously declared target of $250 million of cost savings achievable by bringing government agencies' back office efficiency up to the average of the private sector.
That is despite findings released on Wednesday which show new savings dropped from $87 million two years ago to $20 million last year.
The Treasury's deputy chief executive, Andrew Kibblewhite, says some agencies are having to spend more now upgrading systems for future savings.
Mr English says the Treasury's benchmarking exercise has been useful in identifying where efficiencies can be achieved and now wants agencies to start making those savings.
Spending in 31 agencies on information technology, property and in procurement increased between 2009 and 2011.
The amount spent on human resources, finance and corporate services fell over the same period.
All up, spending fell by $107 million across the two years, with new savings in the most recent year amounting to just $20 million.
Andew Kibblewhite says he is still confident that targeted annual savings of $250 million can be found despite. That would be achieved by bringing efficiency in support functions up to the average of the private sector.