This was the result of an agreement between the two DHBs for the provision of chief executive services.
At a national level, Mr Dyer has for some years been the chief executive lead for employment relations for the DHBs.
This is a challenging portfolio, especially when budgets are tight.
Last year it was reported Mr Dyer and Hutt Valley and Capital and Coast DHB chairwoman Virginia Hope were in mediation following rows over management cost-cutting and the merging of the three DHBs.
"Mr Dyer has made a valuable contribution to both the Wairarapa and Hutt Valley and we wish him well in his future endeavours," said Ms Hope and Wairarapa District Health Board chairman Derek Milne.