The Post Office is looking for a new IT solutions provider to support its transformation agenda.
The organisation is looking to award a two-year framework contract worth between £24 million and £180 million for the design, delivery and support of IT services.
According to the tender document, potential suppliers will need to have a minimum turnover of £20 million a year to bid for the contract.
The Post Office currently has a Horizon IT system, built by Fujitsu, which has been a source of much controversy.
During the busy Christmas period last month the system failed, inconveniencing thousands of customers.
The Horizon point of sale system has also been under fire over alleged problematic accounting – resulting in an angry legal battle with sub-postmasters who say they have been wrongly accused of fraud – and parliamentary committees have also questioned the cost of the system.