Dec 18 (Reuters) - New Zealand's a2 Milk Company on Friday lowered its revenue forecast for the first half of fiscal 2021 and the full year due to weaker informal Chinese demand.

The dairy producer said first-half revenue is now expected to be NZ$670 million ($478.98 million), significantly below its previous forecast of between NZ$725 million and NZ$775 million. ($1 = 1.3988 New Zealand dollars) (Reporting by Nikhil Kurian Nainan in Bengaluru; Editing by Himani Sarkar)