By Pete Sweeney

SHANGHAI, Oct 23 (Reuters) - China's stock indices were down at midday on Tuesday, led by falls for finance and insurance firms, food and beverage manufacturers and miners.

Hong Kong markets were closed for a holiday and will reopen on Wednesday.

The Shanghai Composite Index, which tracks all shares on the Shanghai board, was down 0.61 percent at midday. The CSI300 index of the top Shanghai and Shenzhen listings was down 0.88 percent.

Shares in Air China , which resumed trading in Shanghai on Tuesday after being halted since Oct. 9, opened up 2.2 percent after the company announced it had cancelled a plan for a private share placement, citing adverse market conditions. Shares then sank back to 4.970 yuan ($0.79), flat with the Oct. 8 closing price.

Markets did not react strongly to statements by top securities regulator Guo Shuqing, quoted in state media on Tuesday morning, calling for further research into reducing investment costs for equity investors and listing companies.

The China Securities Regulatory Commission has repeatedly cut marginal transaction costs and fees for investors and brokerages this year, without much effect on investor sentiment.

($1 = 6.2547 Chinese yuan) (Editing by Richard Borsuk)

See the original report here.