The Chancellor's speechwriter Mario Pisani has been given the job of chief press officer responsible for the economy. He starts this week.
The move comes after a space was created by head of news Dan York-Smith, who is moving to a new role within the department.
Pisani will face the challenge of successfully presenting the Government's 'Plan A' of fiscal consolidation, which one source said would be crucial to keeping the coalition hanging together. He will report to head of comms and news Jonathan Black, who took the role in June.
'He will need to show that Plan A is working - that private sector jobs are being created to replace lost public sector jobs, while decisions are being taken fairly in the face of the massive cuts programme,' added the source with close links to The Treasury.
Potential media 'banana skins' facing Pisani could include the potential EU bailout and the continuing culture of bonuses within banking.
The appointment comes as part of a wider move to restructure the Treasury's comms unit over the past year, which has seen the department bring its digital and media functions closer together.
Pisani is a long-term Treasury official, who has also worked in the leader-writers' team at the Financial Times and written articles on economics for the New Statesman.
He will sit alongside senior press officers Matthew Smith, who focuses on financial services, and Anthony Wright, who is press secretary to Danny Alexander, the chief secretary.