LEGISLATORS were warned yesterday against speculating on mainland reaction to the Mandatory Provident Fund. Legislator Hui Yin-fat tried to seek assurances from the Government about China's acceptance of the fund. But in an official reply the Government said: 'It would not be productive to speculate on the reaction to the fund by the Chinese side.' The Government hopes to rush through with primary legislation before the end of the legislative year. Cheung Man-kwong feared that subsidiary legislation, which the Government planned to bring in later, could fail.