Henry, who coached Britain and Ireland's elite in Australia a decade ago, led New Zealand to global glory in October in his eighth year in charge.
His tenure was the longest of any coach of any leading country in the professional game, taking in 103 Tests and two World Cups.
Ex Wales coach Steve Hansen is widely expected to take over from Henry having worked as one of his assistants since 2004.
Hansen has been tipped to bring in former Waikato Chiefs coach Ian Foster and ex-Canterbury coach Aussie McLean.
The 52-year-old took over the Welsh reigns from Henry after The Great Redeemer left the WRU in 2002.
Hansen's time in Wales was sullied by a record 11 straight Test defeats, although the Kiwi has since been credited with putting in place the structures that led to Grand Slam success in 2005.