Striking Greek taxi owners have vowed to continue their protests, after negotiations with the government on new licensing laws fell apart.

The collapse of the talks came as drivers on Monday blocked key highways leading to airports and popular resorts and ports, tying up traffic and disrupting the plans of tourists. The drivers surrounded the Transport Ministry, with the head of the taxi union declaring that the strike would continue indefinitely.

The tourism industry and government have criticized the timing of the strike, which comes at the peak of the economically vital tourist season.

The taxi drivers are protesting recent licensing reforms that increase competition by making it easier to get a taxi license. The government says the new law is fairer and will reduce corruption while creating jobs. But the drivers say it will devalue the current licenses, costing them money.

The new law is part of the government’s economic reform and cutback package in response to the debt crisis that nearly forced Greece into bankruptcy last month. The government says the reforms are necessary under the terms of Greece’s existing bailout deal. The austerity program, which includes pension and public wage cuts and tax and retirement age increases, has sparked anger around the country.