Professor Manfred Wehdorn (L) arrives at Edinburgh Castle
Two Unesco inspectors are arriving in Edinburgh to consider the city's World Heritage status.
The UN's cultural body is considering withdrawing the title, which it awarded in 1995, after the council passed some controversial planning applications.
Unesco is concerned about major new builds, including the Caltongate in the old town and the redevelopment of the St James shopping centre.
The representatives will spend three days touring the developments.
Unesco advisor Professor Manfred Wehdorn arrived on Wednesday morning at Edinburgh Castle for his first meeting.
Dr Mechtild Rossler, Unesco head of Europe and North America, is due to arrive in the city later on Wednesday.
Neil Baxter, secretary of the Royal Incorporation of Architects in Scotland (RIAS), told BBC Radio's Good Morning Scotland programme that he was concerned with Unesco's potential power over Scotland's planning process.
He said: "The idea of Unesco coming to visit and perhaps issue edicts is very worrying in terms of the planning process and due governance of Scotland by Scottish people.
"The planning system comes from government through to the local authorities and the controls are there.
"We shouldn't be stymieing development. If we'd done that in the past we wouldn't have all the good stuff Unesco wants to protect."
Sally Richardson, of the Save Our Old Town Campaign, said when the city had applied for World Heritage status 13 years ago it had signed up to Unesco's criteria for protecting and enhancing.
"We welcome Unesco's visit - they're coming here to offer international experience," she said.
"We're not fighting against development; we're fighting for the right development.
"My children and the children of the Royal Mile Primary School will see buildings on their street demolished to make way for retail-led development that's not going to add to the story of their city."
Delegates are to meet at Seville's 2009 Unesco summit in the summer to discuss the findings.
Edinburgh City Council leader Jenny Dawe said: "I am extremely proud of Edinburgh's World Heritage status and our beautiful architecture, which attracts people to live,
visit, study and invest in Edinburgh.
"We are also a living city that is continuously evolving with all new developments scrutinised and receiving fair appraisal.
"I believe that heritage and development both contribute to the fantastic quality of life that Edinburgh offers."
The Old and New Towns of Edinburgh were awarded world heritage status because of the unique contrast and quality of architecture between the medieval Old Town and the Georgian New Town.