Putrajaya's move to appoint Petron as one of three fuel providers for government vehicles creates a moral conflict, said former prime minister Najib Abdul Razak.
He said surely the question of who owns Petron can create a conflict in terms of decisions and morals.
The appointment of Petron as a fuel provider had raised eyebrows as Prime Minister Dr Mahathir Mohamad's son Mirzan is a shareholder and director in Petron's parent company Petron Corporation, which is based in the Philippines.
Mirzan, however, does not have any shares or a role in Petron's Malaysian operations.