Sanjeev Chada, aged 43, appeared at the court adjoining Castlerea Prison charged with the murders of his sons Eoghan, 10, and Ruairí, 5.
Chada did not speak during the brief hearing and stood with his head bowed as he was further remanded in custody until Sept 13.
Supt Jim Ryan applied for Chada to be remanded for another two weeks where the book of evidence will be served.
Defence solicitor James Hanley requested that Chada’s remand be extended until Sept 20, but Judge Conal Gibbons refused as it would be outside the maximum 30-day detention period.
Mr Hanley consented to Chada being remanded for another four weeks. No application for bail was lodged by the defence solicitor.
Mr Chada, who was dressed in a dark blue sweatshirt over a white V-neck T-shirt, will appear before Harristown District Court on Sept 13.
The bodies of Eoghan and Ruairí Chada, from Ballinkillen, Co Carlow, were discovered near Westport in Co Mayo on July 29 after they were taken on a trip by their father the previous evening.