Transport for London is tendering for an IT service desk contract worth up to £15 million.
The five-year contract covers a service desk for up to 25,000 users across multiple locations - including outside London - escalations management and an out of hours major incident management service.
Service desk support will be offered via phone, email, a web portal, and instant messaging. The logging and tracking of incidents and requests will be via TfL's Remedy IT Service Management (ITSM) tool.
The contract also covers areas like email authentication and configuration, printing, remote access, complaints and working to departmental service level agreements.
TfL estimates the contract will be worth between £10 million and £15 million.
Last month TfL said it was conducting a contactless payments trial that could allow passengers to pay for journeys using a smartphone in future.
TfL is already in the process of upgrading barriers on Tube and rail networks to allow payments using debit cards embedded with near-field communication (NFC) technology. The service is expected to be made available to the public by the end of the year.
According to TfL, the smartphone upgrade would allow phones equipped with NFC systems to also be swiped against payment sensors on gates to pay for journeys.