The area includes the Seven Sisters chalk cliffs near Eastbourne
Campaigners have welcomed an outline plan for the body that will manage the South Downs National Park.
The national park was confirmed in March, 60 years after the area was earmarked for protected status.
Environment Secretary Hilary Benn announced the National Park Authority would have 27 seats, including 14 local authority and six parish councillors.
The South Downs Campaign (SDC) approved of Mr Benn's expectation that the park authority would engage with locals.
The new authority will be required to conserve and enhance the natural beauty, wildlife and cultural heritage of the park and to help improve public understanding and enjoyment.
The Department of Environment, Food and Rural Affairs (Defra) had previously proposed that the overall size of the authority should be between 29 and 37 members.
'Protecting and enhancing'
Following a public consultation, Worthing and Adur district councils agreed to share a seat, helping reduce the number of members to 27.
Robin Crane, SDC chairman, said: "We very much welcome Hilary Benn's statement that he expects the new authority to engage closely with local communities and stakeholders.
"This will be essential if the National Park Authority is going to be successful in protecting and enhancing the South Downs."
The 632 sq-mile South Downs National Park, which stretches from Beachy Head in East Sussex to the edge of Winchester in Hampshire, is the first to be created in England since the New Forest in 2005.
Applications for non-salaried posts on the South Downs National Park Authority were invited in September.
The recruits, who will oversee the formal creation of the park, will start in April 2010, but the park will not formally exist until early in 2011.