Irish people searching for their relatives who immigrated to the U.S. after the Great Depression will be able to trace their relations when the US government publishes their 1940 census online in the coming weeks.

From April 2 the records of 132 million people will be freely accessible for the first time after 72 years of privacy protection lapses, the Associated Press reports. However the records will not be immediately name searchable.

The records will shed light on the transformative decade following the Great Depression. The information may allow researchers to follow the movement of refugees from war-torn Europe in the latter half of the 1930s.

Henry Louis Gates Jr., a Harvard University professor and scholar described the records as a “goldmine” and said the census was a "great contribution to American society".

The Harvard scholar said the data will add another layer of detail to the existing opened census records, which date back to 1790.

"It's such a rare gift," he said.

"Especially for people who believe that establishing their family trees is important for understanding their relationship to American democracy, the history of our country and to a larger sense of themselves."

An enumerator interviews a woman for the 1940 Census. Veiled in secrecy for 72 years because of privacy protections, the 1940 U.S. Census is the first historical federal decennial survey to be made avAP Photo/National Archives at College Park