The Hôpital de la Tour in Meyrin says it will continue to treat patients that are insured by Groupe Mutuel until July.
Earlier this week the insurance company said it was unable to agree a pricing structure with the hospital and so would no longer reimburse patients being treated there.
The hospital says the decision by Groupe Mutuel is unacceptable and harmful.
It’s currently treating around 1,200 people under the company’s cover.
The hospital also says it will fight the decision by all means – including the possibility of taking legal action.