The number of employees on expatriate assignments has increased by 90% over the past three years.

According to Mercer, the trend has almost doubled as part of a continuing move towards globalisation.

Almost half (47%) of companies said they have increased the deployment of expatriates on one to five-year assignments and 38% reported an increase in staff who move across multiple countries on assignments.

Nearly nine out of 10 (86%) employers think employee benefits for expats are a medium or high business priority, but only 26% have a policy for expat benefits and 64% have no procedures in place to measure the success of their international benefit policies.

Robert Lockley, principal in Mercer's international business, said: "Establishing an international policy is essential to stay competitive, maintain geographical consistency and control costs. Even against a backdrop of economic uncertainty there is still competition for the best talent. Companies that are lax in this area will lose out."