Britain's net migration slowed marginally in the third quarter of last year from a record level earlier in 2015, but it remained at three times the government's target, according to data published on Thursday.
Estimated net migration totalled 323,000 in the 12 months to September, down 4 per cent from a record 336,000 in the year to June, the Office for National Statistics said.
Net migration of EU citizens also dropped by 4 per cent to 172,000 in the same period, it said.
Migration is a key issue in political campaigning ahead of a referendum on June 23 on whether Britain should remain a member of the European Union.
Prime Minister David Cameron has claimed that planned restrictions on EU migrants' rights to welfare benefits in Britain, agreed with other EU leaders in a package of reforms ahead of the referendum, will help reduce migration.
Cameron had vowed to cut annual net migration to below 100,000 before national elections last May, when his Conservative party won a parliamentary majority.