Over the past 18 months, the council has been moving its data centre from its location at the Daisy Mill complex to a new facility at the Sharp Project in East Manchester.
The move is aimed at increasing resilience and providing enhanced capabilities including virtualisation, but has now exceeded its original £3.6m budgets.
A statement from the council said: “The scope of the project increased in its approach to the migration to ensure we mitigated risks identified as we investigated the aging estate.”
The council said the new data centre will enable it to reduce its ICT footprint and provide a facility that is scalable if future demand increases.
It said the move means that, for the first time, the council will have ICT back up for critical applications and services as well as disaster recovery for its data centre.
“This was critical investment to reduce impact on citizens, officers and members from ICT issues and outages,” according to a report to councillors earlier this year.
The move is expected to be fully complete by next month.
John Flanagan, the council’s executive member for finance, said: “This approved capital spend will be used to support the move of our data centre to a new location that has been built at The Sharp Project in east Manchester, and will provide the city council with enhanced facilities and improved resilience.”