More than 600 jobs are going at the firm

The firm said 645 jobs would go and all levels would be affected.

It said there was lower demand in the worldwide market in regional jets which has led to fewer orders. Nearly 500 jobs are going in Canada.

Meanwhile, Bombardier has said there is no connection between the growth of its operation in Mexico and the loss of the jobs in Belfast.

About 1,200 new jobs are being created in Mexico.

The factory there specialises in electrical harnessing for Bombardier aircraft.

Peter Williamson of the Amicus union said he was shocked when he heard about the job cuts.

"While we would have been aware that there was difficulties at the company, I think the announcement of 645 jobs on a Northern Ireland scale is enormous," he said.

"What we can do about it is limited.

"I think Bombardier Shorts need to take stock and answer the question - What is the future of Shorts in Northern Ireland?"

Consultations will begin with the unions to try to keep the compulsory redundancies to a minimum.

The firm said it would cut production of the CRJ700/900 regional jets and increase production of the Q400 turboprop.

Part of the turboprop is made in Belfast, but not enough to offset the cutback in regional jet production.

The Belfast jobs will start to go in January 2007, the company said.

Bombardier president Pierre Beaudoin said they had to ensure "we achieve our goal of increased profitability and our success in the long term".

'Success goal'

"This means making difficult but necessary decisions," he said.

"We recognise the impact this decision will have on our affected employees and we will treat them fairly and with respect."

He said the workforce level at Bombardier's Toronto facility where the Q-Series and Global aircraft are manufactured will rise by more than 800 to reflect the increase in production levels.

Mr Robinson said the job cuts would hurt the economy

But he added this would see 1,330 fewer employees at its Montreal-area facilities and at its Belfast site over a nine-month period starting October 2006.

Peter Robinson, DUP MP for East Belfast, said the job cuts would have a severe impact on the Northern Ireland economy.

"I have already spoken to Shorts Chief Executive Michael Ryan and urged him to take steps to offset and mitigate these job losses," he said.

Ulster Unionist leader Sir Reg Empey said he hoped the company would do all it could to attract more work to its Northern Ireland operation.

"The company has advised me that the 90-day notice will allow for negotiations with the trade unions and provide the company with an opportunity to seek new work from the group," the East Belfast assembly member said.

Sinn Fein's economic spokesperson Mitchel McLaughlin said the job losses highlighted the dangers of having an economic policy driven by an over-dependence on foreign investment.

The Foyle Assembly member said: "Sinn Fein has been arguing for sometime that the structural weaknesses in the local economy will not be overcome through an over-reliance on foreign direct investment."

Enterprise Minister Maria Eagle said the government would do all it could to minimise the impact of the jobs losses.

"I can assure (the workers) that government will do all in its power to make appropriate advice and guidance on alternative employment and training opportunities available," she said.