He said his lucky co-worker had turned up on the job but upon discovering the news, the rest of his team had suggested he go home.
The winner, who wanted to remain anonymous when he spoke to the Herald last week, said he stopped at his local supermarket on Monday night to grab something for dinner and checked his Lotto ticket while he was there.
"I handed over my ticket to the lady behind the counter and the words 'Congratulations, you are a First Division winner' flashed up on the screen.
"I asked the lady 'what does this mean?' but the expression on her face gave it away — her eyes were wide and she had a massive grin on her face," said the winner.
"When she told me I had won $19 million, it was like it didn't even register."
Like most Kiwi blokes, the winner prides himself on containing his emotions "so she probably thought I wasn't even excited — if only she knew how I was feeling inside, I was bursting with happiness."
He then started driving home.
"I thought I was doing a good job of holding it all together, but as soon as I started driving my mind began to spin. I just had all these thoughts rushing around."
To clear his head, the winner decided to go for a swim at Snells Beach.
"It was great, the water was cool and I swam out deep. All the rushing thoughts disappeared and I started to feel a lot calmer."
He then headed home to tell his partner the good news.
"While I was swimming I had been thinking about how I wanted to tell her, so I wandered in the house and casually asked her 'did you hear someone in Warkworth has won $19 million?'
"When she turned to look at me I said 'and you're looking at him'. She just stared at me in shock, trying to read my face," laughed the winner.
"When she realised I wasn't joking, we had a big hug and a kiss — it was a very special moment."
The $19.1 million winner said he would now take his time thinking about what to spend the money on.
The Warkworth man was one of two tickets holders who shared the $38m jackpot prize.
The other $19.1 million Powerball winner was claimed by a Wairarapa syndicate of three generations yesterday.