The a2 Milk Company has revised its forecast, after reporting trading performance for its infant formula well ahead of plan in the first four months of the financial year.

The company's forecasting $18 million more in revenue - taking it to $285 million.

It's also putting its before tax earnings at $22 million, up from $12 million.

Managing Director Geoffrey Babidge said infant formula is emerging as a significant growth driver for the Company, and new supply and distribution arrangements in China are yielding positive results.