The strategic comms arm of FTI Consulting (formerly FD) has held the account since 2007, when it picked up the retained brief from College Hill just a year after the retailer floated on the London Stock Exchange.
However, it is understood that FTI has declined to repitch for the brief after Debenhams decided to instigate the process.
Director of investor relations at Debenhams Lisa Williams confirmed that the group was reviewing its financial PR requirements, but declined to elaborate.
The move is thought to be linked to the appointment of Michael Sharp as group CEO in September last year, replacing Rob Templeman.
It is understood that since taking the reins, Sharp, who had previously been deputy CEO from 2008, has instigated a review of a number of the group's third-party advisers, including the firm's corporate broking relationships.
The process remains in its early stages, with several agencies thought to have been asked to provide submissions before the first round of pitches next month.
Some City heavyweights, including those representing fashion retailers and department store groups, are likely to be conflicted out of the process.
Debenhams has bucked the economic downturn to become one of the stand-out performers on the UK high street in recent times.
It reported a sales growth of 3.9 per cent for the 16 weeks to 23 June - a like-for-like revenue increase of 3.1 per cent.
On the back of continued positive sales growth, the group's share price has rocketed by 67 per cent over the past year.
FTI's Debenhams account was previously led by senior MD Jonathan Brill.