The supermarket is conducting credentials meetings with undisclosed agencies before holding a pitch, which will be handled by Haystack.
Waitrose has previously used the digital agency Twentysix London for its online marketing activity. It is not known whether the agency will repitch.
Although a brief has yet to be issued, it is understood that the successful agency will take responsibility for all online advertising and web development.
The search for a digital agency comes shortly after Miles Calcraft Briginshaw Duffy retained the £26 million advertising account in December following a competitive pitch.
This week saw the launch of MCBD's first advertising for the supermarket since retaining the business.