Tourist sites to be classified as essential public services.

Employees at the Colosseum will no longer be able to close one of the world's most famous tourist sites without warning if Italy's prime minister, Matteo Renzi, has his way.

Renzi and the minister for culture, Dario Franceschini, have announced that museums and cultural sites will be added to the list of essential public services after a lightening walk-out for a union meeting on Friday 18 September left long lines of tourists queuing for three hours in the 30C-degree temperatures. In Rome the Palatine, Ostia Antica and the Baths of Diocletian were also closed.

The government's decision to list cultural sites and monuments as essential public services will put employees on the same footing as transport, education and health workers. It will limit union meetings during work hours and prevent industrial action without warning.

The reply of the unions has been quick and angry. The country's largest confederation, CGIL, CISL and UIL is now threatening a national strike.

The unannounced union meeting on 18 September was to discuss staffing levels and hours of work during the coming Holy Jubilee year. Lightening meetings have been frequent in recent months.