The union representing 6,800 Air Canada flight attendants says it is "profoundly" disappointed by an arbitrator's decision that establishes a new collective agreement that includes provisions rejected by employees last month.

"Awarding flight attendants an agreement they rejected a month ago does not in any way address serious workplace issues, and flight attendants are rightfully disappointed and angry," Canadian Union of Public Employees president Paul Moist said in a statement.

Canada Industrial Relations Board (CIRB) arbitrator Elizabeth MacPherson endorsed Air Canada's position on the new provisions in the agreement. The new four year-deal will expire March 31, 2015.

CUPE, which represents the flight attendants, said the government's interference in the collective bargaining process tipped the scales towards the airline.

Labour Minister Lisa Raitt sent the matter to the CIRB after the flight attendants' union rejected an agreement with the airline, even though the union's bargaining committee unanimously recommended it.

Air Canada said it was pleased with the decision to use the contract reached by the "democratically elected" union leadership in September.

"The implementation of a new collective agreement with our flight attendants ends a period of uncertainty for our customers and will allow Air Canada and its employees to move forward together," chief operating officer Duncan Dee said in a statement.

MacPherson said the union had won some concessions from Air Canada in the second tentative agreement.

"An objective comparison of the two tentative agreements reveals that the union bargaining committee did a superb job of extracting additional concessions from Air Canada," she wrote in the 12-page ruling.

Sixty-five per cent of those who voted, did so against the second agreement, although only 73 per cent of the union voted in total.

The union had planned to strike before Raitt sent the matter to the CIRB.

Air Canada's intention to create a low-cost carrier, wages, working conditions and pensions were among the main issues that the arbitrator was ruling on.

"If Air Canada is truly interested in running a professional and efficient company they must invest in their work force. This agreement will leave flight attendants exhausted, frustrated and underpaid," Moist said of the contract.

CUPE said it will be reviewing the decision and consulting with its flight attendants on its next moves.

With files from The Canadian Press