She said the company reviews its external agency needs every three to four years, and that the process is expected to take between two and three months: 'We're still in the process of setting our budgets for the next financial year'.
Retained corporate agency Citigate Dewe Rogerson is not thought to be under threat from the review.
It is understood that the brief will encompass Dairy Crest's full array of consumer brands, the majority of which are held by Osborne. Clover is promoted by The Red Consultancy.
The list is likely to include brands such as Cathedral City and Wexford cheeses, Willow and Country Life spreads, as well as the firm's range of flavoured and unflavoured milks, including the thick-shake Frijj range.
Noble added that the exact make-up of the brief could not yet be confirmed: 'Because we are still reviewing our needs there are no hard-and-fast conclusions as yet. It's still very early on,' she said.
Of the decision to terminate Dairy Crest's arrangement with Osborne PR, Noble said: 'We have had a very long-standing and rewarding relationship with Osborne since 1983. We have changed a lot as a company since then and it is time to look outside of that relationship.'
While Noble did not comment on the type of agency being sought to replace Osborne, it is understood a brief will be dispatched to the major full-service, consumer and specialist food and drinks agencies within weeks.
As part of the overhaul, the firm is also reviewing its in-house reporting structure. The outcome of this will decide who the successful agency reports to.
Dairy Crest is the UK's biggest purchaser of milk, buying three billion litres per year. Formed from the Milk Marketing Board in 1981, it employs 8,000 staff in the UK.
The firm floated on the London Stock Exchange in August 1996 and recorded a 39 per cent rise in half-yearly pre-tax profits to the end of September last year, taking £33.8m.