He was also concerned about the other savings Mr Allen said were needed.
Mr Allen said the changes would save $10 million to $12 million a year, far short of the $24 million originally aimed for.
The $9 million cost of the restructuring would be recovered within a year, and other savings measures such as selling property, moving into cheaper offices and downsizing some posts would produce the $24 million the Government had asked for.
Prime Minister John Key said he didn't believe the process would damage New Zealand's international relations. The ministry needed to modernise and focus more on New Zealand's future relations with Asia. It was important to support Mfat's diplomats, but also acknowledge that change was needed.
NZ First leader Winston Peters criticised the decision to downgrade representation in Europe, including closing the Stockholm Embassy he set up as Foreign Minister in 2008, saying it would save a pittance compared to the benefits lost.
"It's a false economy. Europe is a huge market for New Zealand and you don't neglect a good market."