About 70 percent of companies listed on the Ho Chi Minh Stock Exchange dropped, with blue chips leading the fall. The index was down 0.92 percent at 574.96.

Real estate company Vingroup  VIC.HM fell 0.75 percent, Hanoi-based lender Vietcombank  VCB.HM dipped 0.34 percent and food producer Masan Group  MSN.HM was down 0.52 percent.

Recent gains have pushed some stocks to unusually high levels, which are not supported by their profit growth, said Nguyen Hoai Nam, deputy manager of Maybank Kim Eng Securities.

"Supportive information on the government's policies have been delayed for quite a long time and this has weakened investors motivation," Nam added.

Here is a snapshot of the VN Index  .VNI at midday (0431 GMT.)

    VN Index                                      574.96           

  PREV. CLOSE            580.31            

  % CHANGE               -0.92%            

  LOW                    569.94            

  Change (%) 3-mnth      6.755            

  Change (%) 1-year      19.901            

  52-week low            462.13   30-Aug-13