The union flag will be raised at dawn over Belfast City Hall for the first time since the dispute began last month.
The flying of the flag is to mark the Duchess of Cambridge's birthday, who turns 31 today.
Unrest has continued intermittently since Belfast City Council's decision in December to reduce the number of days the flag flies.
Designated days for the flying of the union flag
- 9 January: Birthday of The Duchess of Cambridge
- 20 January: Birthday of The Countess of Wessex
- 6 February: Her Majesty's Accession
- 19 February: Birthday of The Duke of York
- 10 March: Birthday of The Earl of Wessex
- 11 March: Commonwealth Day (second Monday in March)
- 17 March: St Patrick's Day (in Northern Ireland only)
- 21 April: Birthday of Her Majesty The Queen
- 9 May: Europe Day
- 2 June: Coronation Day
- 10 June: Birthday of The Duke of Edinburgh
- 15 June: Official Celebration of Her Majesty's Birthday
- 21 June: Birthday of The Duke of Cambridge
- 17 July: Birthday of The Duchess of Cornwall
- 15 August: Birthday of The Princess Royal
- 10 November: Remembrance Day (second Sunday)
- 14 November: Birthday of The Prince of Wales
- 20 November: Her Majesty's Wedding Day
- Opening of Parliament by HM The Queen
- Closing of Parliament by HM The Queen