He supplied two of his own horses and borrowed another from a friend to be used in the shoot.
"I think there were about 25 horses used and about two were black, and even they were dyed. It was all-natural product so it was not going to give the horses a reaction.''
Two months later, the manes and tails of his horses were still "quite black'', he said.
He drove around Dunedin trying to find enough henna and eventually they needed to courier some down from Auckland.
The horses were organised by Westport-based Equine Films.
Mr Robinson said it was hard to pick his horses out in the ad, but they "all looked pretty good''.
Otago Peninsula Community Board chairman Paul Pope said the advertisement was a fantastic source of pride for the people of Tomahawk.
"A lot of people in the Tomahawk area really enjoyed it. They saw it as being a real positive for their community.''
The water, beach and horses all looked great, he said.
As well as the scenery, Tomahawk was a good beach to film on in terms of access,
Mr Pope said.
As for the dyeing of the horses, it was the same as the makeup for "any movie star''.
"I know if it was me I'd need plenty to fill in some of the cracks.''
Enterprise Dunedin director John Christie said it was fantastic for Dunedin to be able to promote itself internationally.
"While you don't get the direct link necessarily to location, we know that we are definitely film friendly and those shots of Tomahawk Beach are certainly going to be viewed by a wide audience.''
Enterprise Dunedin was working hard in the film sector to draw in ads, television series' and movies, and those opportunities were starting to present themselves, he said.
