The head of Europe's drugs regulator is braced for disruption following Britain's vote to leave the European Union (EU) and said he feared losing expert staff if, as widely expected, the regulator is forced to decamp from London.

The European Medicines Agency (EMA) approves treatments for all EU countries from its headquarters among global banks in London's Canary Wharf. It is the largest EU body in Britain.

"My concern is to lose experts, to lose staff," Executive Director Guido Rasi told an industry conference on Tuesday.

Most industry watchers believe Britain's decision to leave the EU will mean Europe's equivalent of the U.S. Food and Drug Administration is forced to move to a city within the EU, although there has been no official announcement on this.

EU countries including Spain, France, Poland, Italy, Sweden, Denmark and Ireland have already offered to host the EMA instead of Britain and the tussle over its future location is expected to form part of complex political horse-trading.

The European Banking Authority is also based in London.

"I'm flattered that so many different nations want us but my concern is workability," Rasi told the Pharma Integrates conference.

The EMA employs nearly 900 people, many of whom have made a long-term home in London, since the agency has been based here for the past two decades, he said.

Losing Britain could also leave a big hole in the EMA's scientific capability, since British experts are among the biggest contributors to its drug assessment system.

Rasi said the EMA had set up a task force to address the challenges arising following the Brexit vote but noted that the decision on if and when the agency would move was up to European politicians.

Irish Health Minister Simon Harris, announcing Dublin as a candidate to house the EMA last month, said it appeared inevitable that the EMA would have to relocate from London to another EU member state.

Housing the industry regulator is viewed as a valuable prize for European cities, since it will lead to an injection of a skilled workforce and potentially attract companies.