Chief Executive John Lee on Tuesday said authorities are keeping a close eye on fluctuations in the stock market but have not seen anything unusual going on.

His comments came after the Hang Seng Index dropped to below 15,000 points on Monday, before seeing a recovery on Tuesday morning.

Lee said the market is operating in an orderly manner, but investors should make careful decisions when it is volatile.

"We now have high interest rates, an increasingly complex geopolitical situation. There're also uncertainties in terms of transport and logistics. The market may have different reactions towards the upcoming US presidential election, and there's also an impact from international relations on the stock market," he said.

"The market is sensitive, we'll closely monitor it. Regulators think that the market is responding within their expectations."

The CE also noted that vice president Han Zheng met the management of HSBC on Monday and assured them that Beijing supports Hong Kong as a financial centre.

Lee said with the support of the country and the SAR's own advantages, he is confident in the operation of the city's financial market.