The investigation includes a large number of defendants, Bahrawi said, but did not reveal how many. They are likely to be more than a dozen.

Bahrawi said freezing their funds is "precautionary" and added that the decision comes in light of a large body of evidence suggesting that the said businessmen acquired the land "illegally" and for lower than its real value.

Prosecutors have delegated technical committees to determine the exact area of the seized land and the value of public funds that have been illegally acquired.

Once these committees reach their findings, it will be decided how to move forward with the case, Bahrawi said, adding that the reason the investigation has taken so long is because of the massive size of the seized land.

The decision to freeze the businessmen's personal funds will be the subject of a court hearing on Tuesday, the judicial source told Aswat Masriya.  Celebrity lawyer Farid El-Deeb, also the lawyer of ousted president Hosni Mubarak, said he will be representing Diab in court. 

Complaints against the businessmen were filed before the public funds prosecution accusing them of obtaining "vast areas" of land along the Cairo-Alexandria desert road from the agriculture ministry for low prices, the judicial source said.

The complainants alleged that the accused had turned the land into touristic resorts instead of reclaiming the land for agricultural purposes, in what constitutes unlawful seizure of state land in complicity with the agricultural development and projects authority.

According to investigations, Diab, who owns one of Egypt's biggest private newspapers Al-Masry Al-Youm, established in 1995 Sunset Hills, an investment company. Through the investment company, he acquired 750 feddans - each feddan is roughly equivalent to one acre - paying EGP 300 per feddan. At the time of the deal, a feddan in that area would have sold for between EGP 5,000 and 7,000. 

Gammal, who is also implicated in the investigation, established Degla for Engineering Consultancies in 1977. He is also the father-in-law of Gamal Mubarak, Hosni Mubarak's younger son, who is married to Khadija El Gammal.

Both businessmen were extremely prominent under Mubarak, which was marked by nepotism and the marriage of business and politics. 

The current case upon which the prosecutor's decision is based, dates back to complaints filed in 2007, four years before Mubarak was toppled in a popular uprising in 2011.

Mubarak, both his sons, and many politicians and businessmen who were prominent under the former regime, were taken to court in multiple trials, after Mubarak's ouster, facing charges of corruption and graft. They have mostly been acquitted.

In July the former military general and current president Abdel Fatah al-Sisi amended the graft law to allow defendants in such cases to avoid jail time through financial reconciliations with the government in order to recover much-needed state funds. The amendment was put into effect in August. 

Initiating such reconciliations will guarantee by law that the court will drop the criminal cases, thus ending asset freezes and travel bans taken as precautionary measures against defendants in such cases. 

The amendments cover crimes of misappropriation of public funds, money laundering and graft.