Lucrative contracts being awarded to former Ministry of Foreign Affairs and Trade staffers should be put out for competitive tender, the Greens say.
Figures show that among the $8.4 million spent on external consultants and contractors in the 2011/12 financial year, uncontested contracts worth tens of thousands of dollars were given to former ministry staffers.
Former ambassador Don MacKay was paid $87,530 to prepare for, and chair, a series of United Nations meetings.
MacKay was New Zealand's representative to the United Nations in New York, and later Geneva, Ambassador to Fiji in the early 1990s and New Zealand's Disarmament Ambassador.
None of his contracts were put out to tender because his ''specialist expertise [was] required'', documents show.
Figures from the 2010/11 year showed the trend was not new.
In November 2010, former diplomat Charles Finny, now at Saunders Unsworth, was paid $54,135 to review New Zealand's engagement with Asean.
Green Party foreign affairs spokesman Kennedy Graham said it was not logical to say that just because someone had worked at the ministry they were best for the job.
''In most of those cases, I think I could find another New Zealander who would have comparable expertise and experience, not necessarily inside MFAT now or in the past.''
The bar for tendering work was far too low, he said.
But Foreign Affairs Minister Murray McCully said former ministry staff were only engaged when specialist expertise was required. They were contracted for limited time periods.
''When engaging highly specialised skills that are not available in the market place, a competitive tender is not always required in line with standard public sector practice.''
In the past four years, 16 former employees of the ministry had been contracted back.
It already planned to hire four former staffers in the coming year.
The contracting came as some staff within the ministry were still unsure they would have a job.
Chief executive John Allen announced the final details of the ministry's change programme in May.
It included closure of the Swedish embassy, outsourcing, and almost 80 job cuts.
A spokeswoman for the ministry said yesterday that further announcements on ''third tier'' positions would be made next week.