Qatar Aluminum Manufacturing Co (Qamco) confirmed that partner Norsk Hydro's role as marketing agent for the Qatalum aluminium joint venture had been terminated.
It did not provide a reason.
"Following the termination, Qatalum will assume responsibility for the marketing and sale of its aluminium products on a provisional basis," Qamco said in a statement, adding that it continued to engage constructively with Hydro to ensure an orderly transition.
It was reported late last week that Qatalum had cancelled the commercial agreement under which the plant supplied metal to Hydro; Hydro issued a force majeure notice to customers.
Qamco does not expect any material adverse impact on financial or operational performance at the 648,000-metric-ton-per-year Qatalum, which has only been operating at 60% of capacity since March after the outbreak of the Iran war.
Qamco said it was investigating the circumstances of the disclosure by Hydro, which it said was obliged to maintain confidentiality and coordinate on any public release of information.
Qatalum was founded in 2006 as a 50-50 joint venture between Hydro and state-owned Qatar Petroleum, now known as QatarEnergy, QatarEnergy holds 51% in Qamco.