The usual timing was 10am to 5pm.
On the fourth day of the weeklong 8th Income Tax Fair at the NBR Bhaban in Dhaka's Agargaon on Saturday, the board collected around Tk 2.17 billion in taxes.
The authorities kept the fair open until 8pm also on Saturday after seeing the 'huge' response, the NBR said in a media release.
The fair is being held at 71 other spots across the country.
In the first four days, the collection of income tax is over Tk 12 billion.
The collection in the first four days in last year's fair was around Tk 11.6 billion.
The Board in the release requested everyone to avoid the Agargaon side to enter the fair and to use the Shyamoli end of the street on Sunday due to extra security measures for the 63rd Commonwealth Parliamentary Conference.