NUR-SULTAN- Work may have to be halted at the giant Tengiz oilfield if management and local authorities fail to curb the spread of coronavirus cases among workers, Kazakhstan's chief sanitary doctor said on Wednesday.

There have been 935 cases of COVID-19 reported among Tengiz workers, out of the former Soviet republic's total of 6,969 cases, Aizhan Yesmagambetova told a briefing.

A government commission has adopted a special plan to curb the virus' spread.

"At the moment, it is necessary to ensure control over the implementation of this plan, otherwise it may lead to growth in the number of cases, isolation and natural shutdown of the company or forced shutdown of the company," she said.

Tengiz, developed by Chevron-led joint venture Tengizchevroil, accounts for a third of Kazakhstan's oil output.

The venture has delayed planned maintenance and reduced work on an expansion project in order to curb the outbreak.

Tengizchevroil, based in the western Atyrau province, had no immediate comment on Wednesday.

(Reporting by Tamara Vaal; writing by Olzhas Auyezov; editing by Jason Neely) ((olzhas.auyezov@thomsonreuters.com; +7 727 2508 500; Reuters Messaging: olzhas.auyezov.thomsonreuters.com@reuters.net))