It is understood agencies, including incumbent Mason Williams, have been invited to pitch later this month.
Mason Williams MD Rita Rowe confirmed the agency is seeking to retain the account, adding that the business is normally reviewed regularly.
The review is being overseen by the division's UK general manager Deborah Beckett, who confirmed the review process was underway.
Eurosites is part of the company formerly known as the Airtours Group, and is the division providing package holidays for campers, sitting alongside rebranded MyTravel stores and Airtours package holidays.
The Airtours Group formally changed its name to MyTravel in February.
MyTravel is currently embroiled in a legal battle with the European Commission after it blocked the then Airtours' proposed takeover of rival tour operator First Choice on competition grounds. A ruling by the European Court of First Instance last month favoured the now MyTravel on the issue.