Two Huawei employees who sent a message from the Chinese telecom firm's Twitter account using an iPhone device have been punished, a memo says.
The tweet, posted on New Year's Day, wished followers a "Happy #2019" while displaying "via Twitter for iPhone".
Chinese companies have been trying to steer employees toward Huawei products and away from US rival Apple, according to a report on BBC.
Last year, Huawei overtook Apple in the number of handsets shipped worldwide, making it second only to Samsung.
On Friday, a report by Reuters news agency - citing an internal company memo - said that the Huawei staff involved in the Twitter blunder had been demoted and would be receiving reduced salaries.
The was quickly removed from Huawei's official Twitter feed but was shared by users of the social media site.
The memo said the incident, which was linked to "VPN problems" with a desktop computer, had "caused damage to the Huawei brand", Reuters reported.
Chinese businesses have been attempting to encourage employees to choose Huawei products over Apple in a move to show solidarity with the company's chief financial officer, Meng Wanzhou, who was arrested in Canada on 1 December.
Ms Meng faces extradition to the US on charges of breaking Iran sanctions. The case has increased tensions between the US and China.