Syngenta's chairman has outlined specific criteria that must be met before the Swiss company will seriously consider a takeover bid.

Michel Demare made the comments in a video released on the company's YouTube channel.

He says "a serious proposal to buy Syngenta has to be made at full and fair value."

Demare added the proposal must "recognize for shareholders the inherent combination benefits and it has to provide a high degree of certainty that the transaction will be closed, including compensation in case the deal fails"

In May, Syngenta rejected a $45 billion takeover bid from US rival Monsanto.

Monsanto then offered to pay Syngenta $2 billion if the merger failed to get approval from regulators after 18 months - a condition also rejected by Syngenta.