Mr Lyttle made the calls in letters to British Prime Minister Theresa May, Business Secretary Greg Clark, US Vice President Mike Pence, US Secretary of Commerce Wilbur Ross and Canadian Prime Minister Justin Trudeau, as the US Department of Commerce imposed another tariff of 80 per cent in addition to the 220 per cent last month.
The East Belfast MLA said the interim rulings ran contrary to the spirit of open competition.
“Bombardier is the cornerstone of the manufacturing sector in Northern Ireland, both as the largest employer and enabler of a wider engineering supply chain. Any permanent negative ruling against it would have a massive impact on many livelihoods and the wider economy.
“Alliance has already been in contact with the highest reaches of the UK, US and Canadian Governments, and these letters reiterate the need for the Governments to facilitate and broker an outcome to this dispute.
“There remains a short time in which this matter can still fairly resolved and I hope the Governments take the opportunity to ensure an outcome which supports free and open competition, and protects Bombardier’s critical presence in Northern Ireland.”