The Val Müstair and the Swiss National Park in the eastern canton of Graubünden are to join forces to make a huge Unesco biosphere.
In a statement, the environment ministry said that Unesco had approved the move on Wednesday, but that there were still several conditions that had to be met by 2013.
The biosphere will now measure 371 km², which is twice the size of the current one at the National Park, which is Switzerland’s oldest biosphere reserve.
Unesco agreed to the merger because conditions had partly been met. It had particular praise for the local residents of Val Müstair for their efforts over the biosphere.
But the United Nations cultural organisation called on Switzerland to ensure that a buffer area, to surround the highly protected core zone of the National Park, is put in place by the end of 2013. It also wants a management plan for the whole biosphere.
Biosphere reserves are sites recognised under Unesco's Man and the Biosphere Programme, which innovate and demonstrate approaches to conservation and sustainable development.
Their experience and ideas are shared regionally and internationally within the World Network of Biosphere Reserves. There are 551 sites worldwide in 107 countries.
swissinfo.ch and agencies