Police are currently assisting Fire and Emergency New Zealand at an incident at Hawke's Bay Hospital, involving a chemical spill.
Police were called about 9.35am.
Hawke's Bay Hospital has been partly evacuated.
The District Health Board says the spill happened in the maternity ward and 24 people have been evacuated as a precaution.
Up to six fire trucks with crews are attending, as investigations continue into the incident.
The police are asking members of the public not to attend the hospital at this time unless it is an emergency.
The board is declining to say what chemical is involved.