In a decree, it said the contract had been cancelled "after establishing overcharging" and denounced a "violation of moral principles".

In January 2016 former president Jose Eduardo dos Santos approved a tender awarded to several companies -- including Urbinveste, in which his daughter Isabel is the main shareholder.

The tender was for the construction of a new suburb in the capital Luanda.

Isabel, the former president's oldest daughter and believed to be the richest woman in Africa, said on Twitter on Monday that the allegations of "over-invoicing are unfounded".

"There is a will by new Angolan executive to demonstrate, even without any facts and without proof, that those who worked at the time of the previous executive were dishonest," she tweeted.

In a statement, Urbinveste described the cancellation of the contract without proof "of overcharging" as "incomprehensible ... and incoherent", saying it had followed public procurement procedures.

Relations between Dos Santos's family and Lourenco have soured since the former handed over power in 2017, after 38 years in office.

The new president has embarked on a large-scale clean up of government and state-owned companies, targeting the ex-leader’s relatives.

Within three months of taking control of Angola, Lourenco sacked Isabel as head of the state-run oil company and set about dismantling the empire built by Dos Santos.

Last year Dos Santos' son was fired from his position as head of the sovereign wealth fund.

Most of the dos Santos family are now abroad.