The event, organised by the International Tunnelling and Underground Space Association (ITA), is the latest to be affected as national and international authorities get to grips with the potentially deadly virus.
So far more than 2,800 people have died, most of them in China's Hubei province where the outbreak started.
WTC 2020 had been due to take place in Kuala Lumpur from 15-21 May - but will now run from 11-17 September, the organisers say.
The decision was taken because of the spread of coronavirus (Covid-19) in Asia-Pacific as well as in Europe. “It is not possible at the moment to predict the evolution of this virus and many people could have been forced not to be able to participate," the ITA said in a statement.
“We know that, for some of you, this change of date may not be ideal; however, it seemed to us the best solution to be able to organise this major event for the entire tunnelling industry,” said Dr Teik Aun Ooi, WTC 2020 organising committee chair, and Olivier Vion, ITA executive director.