Is the sentence "There is a large number of labourers who want to migrate to Japan for work." correct? [duplicate]

This site has a good explanation about some of the subtleties of using collective nouns. In particular:

Note that "the number" is a singular collective noun. "The number of applicants is steadily increasing." "A number," on the other hand, is a plural form: "There are several students in the lobby. A number are here to see the president."

It's a peculiarity of "number" as a grouping noun. If you had said "group" instead, then the singular would have been correct:

There is a large group of labourers who want to migrate to Japan for work.

It should be "are". The phrase "a large number of labourers", like "a lot of labourers" and "a dozen labourers", is a plural construction in English and takes the verb "are".