The Children's Minister was informed about serious concerns about a crèche in Dublin more than a year ago.
Katherine Zappone was told at the time how the Hyde & Seek centre in Glasnevin was not registered with Tusla.
However, the crèche in north Dublin continued to be unregistered for another seven months.
Documents obtained by Fianna Fáil's Anne Rabbitte show correspondence between two ministers over the course of several months.
The issue of the crèche not being registered was first raised in parliamentary questions to the Children's Minister in July 2018.
In a response, Tusla said officials were aware of the service and were engaging directly with them.
In August 2018, Finance Minister Paschal Donohoe provided Minister Zappone with a complaint from a constituent regarding the crèche - with Minister Donohoe calling on the Children's Minister to "examine the issues involved" and "respond to me with your views".
The parent in question had raised concerns that the crèche was not registered with Tusla.
They described the centre as 'absolutely disorganised' and noted their fears about the staff turnover.
In a response to her ministerial colleague, Minister Zappone said she'd been assured that Tusla's Early Years Inspectorate was aware of the concerns and was "engaging directly" with Hyde and Seek.
Minister Donohoe received follow-up messages from the constituent in January and March of this year, with the parent in question expressing frustration over the situation.
In a letter on March 26th, Minister Zappone said enforcement proceedings were underway but Hyde and Seek had registered 'as and from 1st March 2019'.
Her letter adds: "It is intended that the Inspectorate will continue to monitor this service closely to ensure on-going compliance with the 2016 regulations."
In a statement, Deputy Rabbitte said: "I find it deeply disturbing to think that identification of childcare facilities breaching regulations is being left to concerned citizens, rather than the Minister and Department.
"The Minister should account for this long delay in bringing a service into line."
Responding to the release of the documents, a spokesperson for the Department insisted Minister Zappone "provided as much information as was possible in the context of an on-going legal case" throughout the process.
The statement explains: "Given the service’s failure to close and failure to comply with all conditions for initial registration, Tusla then initiated legal proceedings against the service in August 2018. These legal proceedings were only finally completed in March 2019.
"During this period, it was not possible for Tusla or the Department of Children and Youth Affairs to provide any further detail in relation to the case, given the risk of prejudicing the outcome of those legal proceedings."
It adds: "It would not have been appropriate for any Government Minister to have interfered with any individual on-going investigation being carried out by Tusla."
The Hyde & Seek chain featured in an RTÉ Investigates documentary earlier this year.
The company has four crèches across Dublin city, catering for children from three months up to 12 years of age.
The documentary reported that while researchers witnessed some examples of good care, the undercover workers started to observe repeated breaches of regulation.
RTÉ also claimed a Hyde & Seek crèche in Glasnevin went unregistered for some 14 months.