HONG KONG, Jan 22 (Reuters) - Hong Kong shares hovered around 19-1/2-month highs for a third session on Tuesday, helped by strength in financials and companies reported to be in talks with Chinese officials on land use for a new economic zone in the southern city of Shenzhen.
The Hang Seng Index closed up 0.3 percent at 23,658.99. The China Enterprises Index of the top Chinese listings in Hong Kong rose 0.6 percent.
In the mainland, the CSI300 of the top Shanghai and Shenzhen A-share listings closed down 0.5 percent at 2,596.9, slipping off Monday's 7-1/2-month closing high. The Shanghai Composite Index closed down 0.6 percent at 2,315.1.
* China International Marine Containers Group surged 18.3 percent, China Merchants Holdings jumped 8.8 percent and Shenzhen International Holdings soared 21 percent. Hong Kong media reported that all were in talks with Shenzhen's city government on land use in the new Qianhai special economic zone, traders said. They collectively own 27.5 percent of Qianhai's total land mass, the same report said.
* At least 10 companies issued profit warnings overnight. Vanke Properties Overseas slumped 7.5 percent after warning it expects a "significant decrease" in full-year net profit, due mainly to the purchase in May of a Hong Kong-based property company by its parent, China Vanke Co.