Ten agencies are being sought to compete for the account to last for an initial three-year period. This will be reviewed annually and may be extended for a further three years.
The pitch follows a three-year review of the existing contract, which is held by The Communication Group.
WDA head of PR Helen Butler, to whom the successful agency will report, said details of the brief are still being decided. But she added that it is likely to better reflect the transformed political makeup of Wales, notably the creation of the regional Assembly in Cardiff.
She said: 'There has been a lot of change in the last three years, it's been an exciting time politically and there are new audiences.'
The pitch follows an overhaul of the WDA's in-house comms function earlier this year (PRWeek, 26 April). This included the scrapping of the director of media and comms role to be replaced by the newly created head of PR role, which Butler filled in October.
In scrapping the director level comms role, marketing director Gareth John said there was a need to have the WDA's most senior PRO more involved in day-to-day work.
John told PRWeek in April that he expected the organisation's external PR agency to concentrate on strategic and tactical work and for the in-house team to handle day-to-day inquiries.
A long list is expected to be in place by 8 January next year and the contract starts in April.
One scheme that the WDA is involved in is the Welsh Assembly's Broadband Wales programme. The WDA has been tasked with delivering parts of the programme relating to handing out subsidies for SMEs wanting satellite connections.