* HSI -0.1 pct, H-shares +0.4 pct, CSI300 -1.6 pct
* Chinese airlines A-shares tumble on bird flu jitters
* HK developers weak after poor weekend secondary market sales
By Clement Tan
HONG KONG, April 8 (Reuters) - China shares returned from a four-day holiday weekend at their lowest since late December early on Monday, as bird flu worries hit tourism-related sectors while the property sector lost ground on more sales curbs.
Hong Kong property developers were among the underperformers after local media reported disappointing secondary housing market sales over the weekend, tipping the Hang Seng Index down 0.1 percent at 0200 GMT.
The CSI300 of the leading Shanghai and Shenzhen A-share listings was down 1.6 percent at 2,443.4, its lowest since late December. The Shanghai Composite Index was down 1.7 percent.
The China Enterprises Index of the top Chinese listings in Hong Kong rebounded 0.4 percent from a four-month closing low. Hong Kong markets slumped on Friday on bird flu jitters.
On Monday, Air China shares in Shanghai were headed for their heaviest loss in nearly 2-1/2-years, diving 7.3 percent, while Shanghai Airport sank 5.5 percent.
Airline stocks in Hong Kong retraced some of their heavy losses, with Air China rebounding 2.5 percent after slumping 9.8 percent on Friday, its worst single-day loss in nearly four years.
China is confident it can control an outbreak of a new strain of bird flu, a senior Chinese health official said on Sunday as the World Health Organization (WHO) said there were now 21 human cases of the H7N9 flu with six deaths.
Bird flu concerns were also cited by Hong Kong media as accounting for lackluster secondary housing market sales over the weekend. Cheung Kong Holdings lost 1.4 percent, while New World Development dived 3.7 percent to its lowest since early January.
The Chinese property sector also on the defensive after the official China Securities Journal reported on Monday that Beijing is likely to raise down-payment requirement for buyers taking commercial loans to purchase second homes to 70 percent.
China Vanke tumbled 3.2 percent in Shenzhen, while Poly Real Estate fell 3.4 percent in Shanghai and China Resources Land slid 1.9 percent in Hong Kong.