The human remains that stopped work on the Huntly section of the Waikato Expressway late last month was that of a young male.
Once excavated, the remains, which appeared to have been buried in a kumara pit, were sent to Auckland for analysis.
NZ Transport Agency's Hamilton highways manager Kaye Clark said archaeologists had found that the koiwi was aged between 17 and 20 and was reasonably healthy apart from abnormalities in the lower spine and having extremely worn teeth for a person of that age.
"At this point we have not been given a specific date or time period to how long this koiwi has been buried but material from the site has being sent for carbon dating," said Mrs Clark.
The koiwi was reinterred at Taupiri on April 5.
Work stopped at the site of the koiwi discovery for five days, resuming on April 4. Work did not stop on other parts of the project following the find.