Portugal has ordered a freeze on the bank accounts of the billionaire businesswoman Isabel dos Santos, who is currently the subject of a criminal investigation in Angola.

The public prosecutor’s office in Lisbon confirmed reports that dozens of personal and corporate accounts belonging to Dos Santos and her husband, Sindika Dokolo, were the subject of a seizure order.

The daughter of the former Angolan president José Eduardo dos Santos, she is said to be Africa’s richest woman, with a fortune estimated at $2.2bn.

The order was prompted by a request from Angola, where Dos Santos has been named as a suspect in a criminal investigation into the misappropriation of funds from the state oil company, Sonangol.

“We confirm that the public prosecution service requested the seizure of bank accounts, as part of the request for international judicial cooperation from the Angolan authorities,” the Portuguese prosecutor’s office told news agency Lusa.

Q&A What is the Luanda Leaks investigation? Show Hide The Luanda Leaks project is based on a trove of 715,000 emails, charts, contracts, audits and accounts detailing the business operations of Isabel dos Santos, the daughter of the former president of Angola. The files were initially obtained by the anti-corruption charity Platform to Protect Whistleblowers in Africa (PPLAAF), which shared them with the International Consortium of Investigative Journalists (ICIJ). The documents, which cover a period between 1980 and 2018, have been reviewed by more than 120 journalists from 37 media outlets, including the Guardian, the BBC and the Portuguese newspaper Expresso.

Dos Santos was appointed the chair of Sonangol as her father was nearing the end of his 38-year term as president. Prosecutors are investigating the transfer of some $115m in consultancy fees which she allegedly authorised while at the helm of the company.

A spokesperson for Dos Santos did not immediately respond to a request for comment. She has previously rejected any suggestion of wrongdoing, describing allegations against her as “extremely misleading and untrue”. Dos Santos has said she is the subject of a “a very concentrated, orchestrated and well-coordinated political attack” led by Angola’s current president.

The empire she and her husband control spans banking, diamonds, oil, telecoms, property, engineering and supermarkets in Angola and Portugal. The couple own a number of homes in London and she has in the past referred to the UK capital as her main family home.

In January, the Luanda Leaks investigation revealed numerous schemes apparently used by Dos Santos and her husband to obtain Angolan state funds during her father’s presidency. The revelations were based on a leak of 715,000 files obtained from administrators of the Dos Santos empire, obtained by the International Consortium of Investigative Journalists and shared with news groups including the Guardian, the BBC and the New York Times.

Portugal is now the second country to have imposed a freeze on Dos Santos. In December, personal and corporate accounts belonging to her, her husband and a key adviser were frozen in Angola. Prosecutors say deals between the couple and state-owned businesses in the diamond and oil sectors harmed the state to the tune of $1bn. Angola is demanding compensation.

The Angolan attorney general, Hélder Pitta Grós, reportedly requested the Portuguese seizure in a letter sent following a visit to Lisbon on 23 January, when he met with his Portuguese counterpart in order to request help with the prosecution against Dos Santos.

“At the meeting in Lisbon between the attorneys general of Angola and Portugal, and following requests for cooperation, the freezing of Isabel dos Santos’s personal and company accounts was requested as part of the seizure process in Angola,” a spokesperson for the Angolan attorney general told O Jornal Económico, adding that that request “was formalised in a letter rogatory sent after the visit, where these steps by the Portuguese justice are requested.”.