Popular BBC television documentary Coast is being filmed in Dunedin and is tipped to give the region tourism publicity ''you couldn't afford to pay for''.

Coast began 10 years ago, taking journeys around the coastline of the United Kingdom and uncovering stories relating to both their natural and social histories.

More recently, the show has expanded to cover the coastlines of its neighbouring countries, and in 2013 Australia's coastline featured.

Now, it is New Zealand's turn.

A BBC film crew has been in Dunedin for the past week with presenter, historian, archaeologist and author Neil Oliver, filming coastal landmarks such as the albatross colony on Otago Peninsula, Cargill's Castle at Highgrove and Tunnel Beach at Blackhead, as well as Port Chalmers.

Mr Oliver said filming began in February and footage of much of the North Island coastline and Fiordland had been collected so far.

He had been enchanted by the areas he had visited, but filming had been a rush and he was yearning to just sit down and appreciate the surroundings.

''Some places you visit and you wish you could be there for a week, but in reality you're only there for a day.''

He said he would have quite happily spent twice as long in the Bay of Islands, but when it came to Fiordland, he was happy with the whirlwind visit.

''Coming from Scotland, where we've got the legendary midge, I knew what to expect.

''The sandflies in Fiordland were almost as unpleasant,'' he said.

The six-episode season is expected to be broadcast later this year or early next year, in New Zealand first, and then on the BBC in the United Kingdom.

From there, it would be broadcast in other territories, he said.

''Previous seasons of the show have been shown in 30 to 40 countries.

''Coast Australia was very popular. New Zealand will be just as popular, so it will be seen in many countries around the world.''

Enterprise Dunedin director John Christie said the programme had the potential to give a significant boost to the region's tourism.

''We know there is definitely a direct economic impact from having film crews in the city while they are undertaking any film work.

''We also know that in some cases you get profiled as a city which has got huge value in terms of international marketing. It could well bring tourists here.

''You couldn't afford to pay for the sort of publicity that you'd get through a programme that has such a wide audience.''

john.lewis@odt.co.nz