The World Trade Organisation (WTO) deemed the EU ban illegal because it was not based on proper scientific research.

The EU consequently conducted an independent scientific research project and changed its laws to comply with the WTO ruling.

But the US and Canada have still not lifted their sanctions, prompting Monday's action.

Sanctions must go

"The EU ban on certain growth-promoting hormones is now in full respect of our international obligations", said EU trade commissioner Pascal Lamy.

"There is no reason why European companies should continue to be targeted by sanctions when they export to Canada and the United States", he continued.

The complaint is the first step in the procedure, which can be quite lengthy.

The EU has asked for consultations with the US and Canada. If no progress is made within 60 days, the case goes to a WTO panel, where the procedure lasts another eight to nine months.

"Obviously we could save a lot of time and effort if the US and Canada just lifted the sanctions", said Mr Lamy's spokeswomen.

Although over half of disputes are settled at the consultation phase, without going to the panel, the spokeswoman said it was "very difficult to say" what would happen in this case. The EU expects a response in the coming days, she added.

"The message we are sending is loud and clear ... the sanctions must go", she told reporters.

The EU's announcement follows recent transatlantic squabbles over government aid to aerospace companies Boeing and Airbus.