Shares of Tesla tumbled 19 per cent on Wednesday (US time), hitting the brakes on a dramatic rally after a senior executive warned the coronavirus outbreak in China would delay deliveries of Model 3 cars made at its Shanghai plant.

With Tesla still up about 27 per cent since the company posted its second consecutive quarterly profit a week ago, Canaccord Genuity cut its rating on Tesla to "hold" from "buy," further shrinking the already small number of analysts who recommend buying the stock.

Production at Tesla's Shanghai plant has been delayed until at least February 10. Credit:Bloomberg

Tesla Vice President Tao Lin said on the Weibo social media platform that car deliveries from its new Shanghai plant would be temporarily delayed and that the company planned to restart production on February 10.

The $US2 billion ($3 billion) factory is a key part of chief executive Elon Musk's plan to make more than half a million automobiles this year.