SINGAPORE—Tech giants such as Facebook Inc., Alphabet Inc.’s Google and Twitter Inc. would be required under a draft law introduced Monday in Singapore to immediately issue corrections of false information published on their platforms and inform users when they might have been exposed to inaccuracies.

The legislation is some of the most potentially sweeping anywhere against so-called "fake news’’ and would set a precedent for the global issue, which has seen a backlash against social media. Facebook, Twitter and Google all...