The Government is to publish new figures which could reveal a higher number of EU migrants are working in the UK.
HM Revenue and Customs said it will provide statistics on how many National Insurance numbers are actively being used by EU citizens.
The figures will be given to the Office for National Statistics to publish in May, just weeks ahead of the EU referendum.
Current figures about the number of EU citizens living in the UK are based on the number of people entering the country but concerns about the quality of the data was raised last month by the statistics watchdog. The UK Statistics Authority warned that discrepancies between the sets of figures could undermine public confidence.
Head of the watchdog Ed Humpherson said figures for National Insurance numbers issued to foreign nationals are traditionally higher than the ONS's international migration estimates.