This is due to the huge amount of data that was seized and analysed by the public prosecutor's office in Cologne during a search in the summer, said spokesman Ulrich Bremer when asked by the Catholic News Agency (KNA).
He thus confirmed a report in the "Kölner Stadt-Anzeiger" (Tuesday).
Woelki is being investigated on charges of perjury and possible false affidavits.
All statements are related to press disputes between the Archbishop and the "Bild" newspaper.
The matter centres on when Woelki had detailed knowledge of two cases of abuse. In the summer, the public prosecutor's office searched several properties belonging to the Archdiocese of Cologne and its email service provider.
In addition, the cardinal's mobile phone and laptop were temporarily seized and the data "mirrored".
According to the public prosecutor's office, 800,000 confiscated emails with half a million attachments from the archdiocese and around 120,000 chat messages and attachments from the cardinal's mobile phone are to be examined.
After the search at the end of June 2023, it took five months to process the data so that it could be searched using suitable search programmes.
Analysing the mobile phone data is a matter for the boss
Detectives from the Cologne State Security Service have been analysing the email traffic since November, according to reports.
Head investigator Ulf Willuhn, head of the political department of the Cologne prosecution authority, has made the analysis of Woelki's mobile phone data a top priority.
"In view of the applicable presumption of innocence and the protection of personal rights, this is appropriate and necessary in this case due to the particular sensitivity of the data secured from the cardinal himself," said Bremer.
It was important to reduce the risk of leaks. Media representatives had learnt about the search of the archbishop's house in the summer in advance, against which Woelki filed a criminal complaint for betrayal of secrets.
On the one hand, the press dispute concerns the case of the former president of the children's missionary organisation "Die Sternsinger", Winfried Pilz, who died in 2019.
The clergyman spent his retirement in the diocese of Dresden-Meißen, which had not been informed of the allegations by Woelki's predecessor, Cardinal Joachim Meisner.
Woelki is defending himself with affidavits against the "Bild" claim that he decided not to make up the information.
He only found out about the allegations against Pilz at the end of June 2022 - a few days before the Archdiocese of Cologne made the case public.
The other case relates to a priest promoted by Woelki.
Also in the form of an affidavit, the cardinal contradicts the "Bild" report that he was aware of a police warning about the priest's involvement in youth work and a conversation protocol with accusations from a man when he was promoted in 2017.
He repeated this statement at a hearing before the district court at the end of March and added that he had no knowledge of these incriminating documents "to this day".
He swore to this at the insistence of the Axel Springer publishing house.
This was followed by a complaint of perjury - including a reference to a letter signed by Woelki to the Vatican about the allegations against the promoted priest.