Demetriou says cases like these set a good example for other businesses.
"We hope cases like these encourage other organisations to look at their electronic messaging practices and help educate the public on the rules around any messages they receive.
PB Tech general manager Darren Smith told the Herald the company had sent the emails for years and didn't know it was in the wrong.
"It wasn't intentional, we didn't quite understand the rules," Smith said.
It came to light when members of the public complained to the DIA, he said.
He understood that about five people complained.
There have been relatively few official sanctions for New Zealanders or their businesses sending spam.
In 2015, an Australian businessman was fined $95,000 in Auckland for sending almost a million spam emails to New Zealanders after buying addresses from a data company.
Wayne Mansfield of Perth had more than 80,000 email addresses in his database to which he sent unsolicited messages about his business seminars over two months.
In 2009, A Kiwi "mastermind" behind an international spam network was ordered to pay US$15.15 million ($21.33m) by a US federal judge.
Lance Atkinson, originally from Christchurch, was identified by anti-spam organisation Spamhaus as the ringleader of the world's largest spam gang, marketing male enhancement pills, prescription drugs and weight-loss pills, the US Federal Trade Commission (FTC) said at the time.