The European Medicines Agency could see higher-than-anticipated staff losses when it moves to Amsterdam, according to Executive Director Guido Rasi.

A staff survey conducted by the Agency last year found that only 19 percent of employees would likely leave due to the Brexit-induced move, but in an interview with Bloomberg Rasi has admitted that hitting that target will be "very challenging".

“The level of uncertainty is still high because of practicalities,” he said. “We are monitoring it on a daily basis.”

He cited a range of potential issues, including housing searches, rising costs of living, finding jobs for spouses and partners, and uprooting as many as 500 children. Short-term contractors could also be affected as Dutch law allows them to become permanent after two years.

Rasi said the move could also delay training in areas such as big data and gene therapies and slow improvements to technology systems - but he noted that the EMA has a reserve list of more than 1,000 applicants that it can tap when it needs to fill vacant roles.

“There will be a dip, but we will be back and we will be back as strong and as good as ever,” he said.