On that occasion, officers took him to Hawke's Bay Hospital, but the man went home before seeing a psychiatrist.
Police officers then visited his home at about 2.40pm and arrangements were made for him to be seen by mental health professionals at home.
The National Poisons Centre contacted police an hour and a half later, saying someone had called them after drinking a substance.
Police searched for the caller after identifying the area where the call was made, but could not find him.
The next morning, a body was found in the same area where the "drunk" man had been.
It was identified as the same man who had been taken to hospital the previous day. A mostly-empty bottle of a substance and the cellphone used to call the poisons centre were found at his home.
The ICPA agreed with a police practice review finding that the officer at the petrol station should have taken action when told about the drunk man.
Police dealings with the man earlier in the day were appropriate, both reviews concluded.