Vodafone has asked three of the Big Four accountancy firms to clear the decks in preparation for a potential audit re-tender.
PwC is currently managing the collapsed mobile retailer Phones 4U and has been drawing up plans to sue Vodafone for its alleged role in the downfall of the firm.
Phones 4U fell into administration in September 2014 after leading mobile firms stopped supplying the retailer.
Insiders stressed Vodafone has yet to make a firm decision on PwC's future, instead highlighting Vodafone had contacted PwC's rivals to review any current engagements with the mobile firm and consider if they represented a conflict to performing the audit in the future, Sky News first reported over the weekend.
Vodafone and PwC declined to comment.