It is expected that an agency will be hired as part of a consortium led by landscape and planning experts which is needed to represent the body at the almost certain public inquiry into the plans.
According to Countryside Agency senior countryside officer David Stock, the aim is to hire a lead agency with expertise in landscape architecture, which will then subcontract the PR side of the brief to a more appropriate consultancy.
PR is seen as vital to promoting the body's 'expert witnesses' at the inquiry, which, according to Stock, is '99 per cent certain' to go ahead due to the scale of opposition to the plans.
The body expects at least 800 objections at the inquiry, mainly on the contentious areas of the proposed boundaries, both by those included in, and excluded from, the park.
The public consultation exercise by the Countryside Agency into the setting up of the park attracted more than 6,500 written responses, two-thirds of which were specific to the boundary.
The successful consultancy will report to the body's national park designation team, based at its London offices.
It is hoped work can start in June. An announcement by the Department of Environment, Food and Rural Affairs on whether an inquiry will go ahead will be given within the next two months.