Trinity Biotech last night announced that it was suing one of its US distributors, Inverness Medical Innovations, for breach of contract.

Inverness has the exclusive rights to distribute a Trinity Biotech product used to test for infectious diseases.

Last night, a statement from the Irish company to the stock exchange alleged that Inverness had attempted to convert customers to a product made by Zeus Scientific by falsely claiming that Trinity's test was not available and was being discontinued.

Inverness was unavailable for comment.

Trinity also alleged that Inverness had made "huge efforts" to make the Zeus Scientific kit look identical to the Irish company's. Inverness sells the product under its own label, and thus customers cannot identify the manufacturer, Trinity said.

The contract with Inverness is due to end on September 30th, 2004. At that point, Trinity and Inverness will be able to sell the product separately under their respective labels.

The company said the agreement entitled Trinity to sell any of its products in the US in direct competition with Inverness, and would exercise this right immediately.

Last night, Trinity chief executive Mr Ronan O'Caoimh said: "We must take action in this case to protect our position and will therefore offer the products in the US market immediately."