The car company has held credentials meetings with a number of undisclosed agencies, and is drawing up a shortlist to pitch for the business. Porsche's in-house marketing team will handle the review.
The move will come as a blow to the incumbent, Clark McKay & Walpole, which has held the consolidated account for the past six years.
The agency was hired for the above- and below-the-line tasks, after a competitive pitch in 2001, which ended Leagas Delaney's role with Porsche.
In January, the car-maker reported pre-tax earnings of £954 million for 2006/07. Its results were boosted by its recently increased stake in fellow car brand Volkswagen, which saw earnings rise by £355 million.
Porsche declined to comment on the search.