The number of asylum seekers sent by Australia to Nauru now exceeds 500, with 43 flown from Christmas Island early on Monday.
The group of single men were mostly Iranian or Pakistani.
The detention camps on the island, which have been operating for nearly a year, are now housing 529 people - mostly single men, but seven families, including 12 children, were sent last month.
Dozens of the inmates have been on the island for nearly a year.
There is no indication from the Nauru government whether the children are receiving the schooling that had been promised when the detention centre re-opened in September last year.
Seven weeks ago Nauru's secretary of justice said they were just days away from declaring the first refugees at the camp, but to date no such announcement has been made.