The new South Downs National Park officially comes into being tomorrow, giving greater protection to a huge swathe of green space across Sussex.

It’s bound to be a boost for tourism in the area but not every business owner is welcoming it with open arms.

One of the main differences between the new South Downs National Park and others is the amount of people living and working within its boundaries.

There are more than 100,000 residents and hundreds of small businesses, from working farms, food producers and vineyards to office-based enterprises.

The level of economic activity is borne out by the fact that the 14 local authorities that are part of the national park receive an average of 4,000 planning applications every year, more than four times as many as other British national parks.

Members of the new South Downs National Park Authority (NPA), who take up their positions officially tomorrow, will have to meet the challenge of conserving the natural elements of the national park while fostering its economic output.

Mike Roberts, director of Ridgeview Winery, in Ditchling, is a keen supporter of the park but worries that planning restrictions might be too severe.

He believes the South Downs, which share many geological similarities with the Champagne region of France, will soon become world famous for its sparkling wine.

His vineyard currently produces 200,000 bottles a year but that could double by 2012.

He said: “There is going to be the need to expand capacity. I don’t want to be negative as I think the park is a great idea but the importance of agricultural activities must be recognised.”

Farmer Trevor Passmore, who owns the 1,000-acre Church Farm at Coombes, Lancing, said the public needs to realise the national park is home to thriving businesses.

He said: “I have had people asking me what I’m going to do now that I have sold the farm.”

This attitude has already led to problems and Mr Passmore said he has had to warn dog walkers who strolled through his dairy herd.

He said: “I told them that the footpath was over there but their attitude was ‘this is ours now’.

“We don’t want an accident and people have to know this is a working farm.”

Mr Passmore is also concerned that national park rules may conflict with existing regulations covering farming.

He added: “EU regulations mean that if you have a dairy farm you need to build a container to hold the slurry. But I know of a farmer in the New Forest who was told that he couldn’t do that because of national park rules.

“He is now in a situation where he has to decide whether or not he wants to continue farming.”

Ken Bodfish, one of seven national members of the NPA appointed by Hilary Benn, Secretary of State For Environment, Food and Rural Affairs, said the national park should be good for business.

He believes it should simplify the planning process because previously the 14 local authorities each had their own planning policies.

Mr Bodfish is also confident that “sustainable” economic development will be supported.

He said: “The national park is not intended to be held in aspic and one of the authority’s duties is to foster its economic and social wellbeing.”

Fellow NPA member Sir Sebastian Anstruther, who manages his family’s 3,200- acre Barlavington Estate, near Chichester, added: “Evidence suggests that the local economy benefits from national park status.

“Our hope is that businesses across the national park, including landowners and farmers, will benefit from operating within the boundary and will work in partnership with us to seize the opportunities that national park designation offers.”

Tourism businesses are unsurprisingly in favour of the national park.

Lizzie Esler, owner of Nash Manor B&B and conference venue, in Steyning, said: “The national park will attract more walkers and cyclists into the area.

“Last year we saw a lot more people from across the UK coming to visit and looking at the diary that trend is set to continue this year.”

She believes more business through her doors will also benefit neighbouring food producers.

She said: “We use local producers so hopefully it will lead to more employment at these businesses.”