In response, city spokeswoman Priya Reddy said on Thursday that the city was "undertaking a plan to improve service delivery" which involved transforming the city into a customer-centric organisation.
"Part of this means adapting the city structure to meet the requirements.
John Comitis and his head coach, Eric Tinkler, have worked feverishly and quickly in assembling a squad capable of being competitive in its debut PSL campaign.
A host of signings have seen the City squad swell to 23 and Comitis said he was looking at perhaps another two additions before the season kicks off on August 23, to bring the number to 25 players.
About half the city's employees are Imatu members.
Bruwer said the union had been caught off guard by the notices and had requested an urgent meeting with the city.
The latest two signings - Brown and Motloung - are an interesting and exciting mix for City.
Management staff have been advised that their jobs may be affected by this as part of a consultative process between the city government and the recognised unions, facilitated by the CCMA." Reddy said the outcome of the process was not yet known.
According to notices handed to employees, the process would be concluded by December.
In her address to the council last month, mayor Patricia de Lille said the ODTP was necessitated by changes to planning methodology and pioneering transversal management in the city's administration.
Cape Town - Cape Town City’s commitment to building a diverse football squad to appeal to the multi-cultural city in which it resides, continues apace with the signing of Australian James Brown and Khayelitsha’s Samora Motloung.
Imatu said the move was "premature" and "irresponsible".Imatu's regional manager for Cape Town, Etienne Bruwer, said: "This move by the City of Cape Town could have devastating consequences on service delivery and could result in large-scale loss of critical skills that have enabled the city to grow and develop thus far." The city employs about 26 000 employees with 66 percent of people from employment equity target groups in the three highest levels of management.