"Upon arrival, we found the defendant's 1-year-old daughter in her car seat, lightly clad, in a car outside the Kuripuni Tavern," he said.
Police said when breath-tested the man was found to have a breath alcohol level of 968mcg, which is more than twice the legal limit.
"Every child deserves the right to be looked after and cared for, not neglected and left in a vehicle outside a pub on a Saturday night," said Mr Heathcote.
"We have notified the appropriate agencies, who will ensure that the ongoing welfare needs of these three children are met."
Child, Youth and Family central regional director Karen Petrie said all the children were returned to their mother on Saturday night and were safe and well. She said the agency had begun an investigation into the case and was assessing what support the family needed.
"The actions of this father are irresponsible and could have easily placed the children in danger," she said. "The baby left alone in the car should never have been left unsupervised."
The Kuripuni Tavern is owned by Trust House.
Chief executive Bernard Teahan said the incident was inexcusable. Staff were alerted by a member of public that the baby had been left in the car just before 11pm, and Mr Teahan said staff acted appropriately and called the authorities straight away.
"We advised the police immediately and let them take the appropriate action," he said. "In my opinion, my staff did the right thing," Mr Teahan said.
The man had obviously been drinking elsewhere before stopping at the pub, he said.
"Someone having a drink with children in the car, that's totally inappropriate," he said. "It's just inexcusable and hard to understand."
A man will appear in the Masterton District Court on Thursday facing charges, including driving with excess breath alcohol and wilful neglect of children.