FIFA refereeing chief Pierluigi Collina has broken his silence on the controversial World Cup Round-of-16 clash between Argentina and Egypt, firmly rejecting allegations that match officials favoured the defending champions after the African nation accused referee Francois Letexier of making "serious" errors and demanded his removal from the tournament.

A member of Egypt's coaching staff is shown a red card by referee Francois Letexier (REUTERS)

The Egyptian Football Association (EFA) reportedly lodged an official complaint with FIFA after Argentina's dramatic 3-2 comeback victory in Atlanta, seeking explanations for a series of contentious refereeing decisions and calling for Letexier and his officiating team to be removed from the remainder of the World Cup.

The complaint came a day after Egypt made explosive allegations that the tournament had been "directed" towards Argentina. Head coach Hossam Hassan accused FIFA of favouring the defending champions, saying: "Perhaps they wanted to keep the world champions in the competition. Perhaps they wanted Messi to stay in the running."

In an interview published on inside.fifa.com on Thursday, Collina acknowledged that refereeing decisions will always be debated but drew a firm line at questioning the integrity of match officials.

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"Constructive discussion about decisions will always be part of football, but unfounded allegations have no place in our sport," Collina said.

"Nobody can question the integrity of the FIFA World Cup match officials... Nobody can claim that FIFA refereeing can be influenced by anyone, not even by the FIFA president (Gianni Infantino)."

Collina also warned that such accusations could have serious consequences, saying they risk exposing referees and their families to abuse and threats.

Egypt's biggest grievance centred on VAR overturning Mostafa Ziko's 58th-minute goal after identifying a foul by Marwan Attia on Argentina defender Lisandro Martínez earlier in the attacking phase.

Defending that decision, Collina insisted VAR had acted within protocol.

"We believe that a foul is a foul," he said. "Regardless of whether the foul appears 'obvious', if the referee did not see it on the field of play, the VAR can intervene."

Egypt also protested the officials' decision not to review a potential penalty moments before Enzo Fernández scored Argentina's winner, with captain Mohamed Salah going down inside the box following a challenge from Julián Álvarez.

Collina backed the match officials on that incident as well, saying both the referee and the VAR correctly judged the contact to be "normal football contact."

"Stepping on an opponent's foot is a foul, whereas a defender who touches the ball first and then makes normal football contact has not committed a foul," he said.

While acknowledging that some decisions will always involve an element of subjectivity, Collina said FIFA remained satisfied with the application of VAR protocols throughout the tournament.