The DUP has called for new guidance on the flying of the Union flag to be extended to Northern Ireland.
The national flag is to be flown on UK Government buildings every day in a bid to unite the nation.
At present, Union flags are only required to be flown on UK Government buildings on designated days, but the new guidance from the Department for Digital, Culture, Media and Sport will ask for it to be flown all the time in England, Scotland and Wales.
However in Northern Ireland it will continue to be flown only on designated days.
Flags and emblems are a contentious issue among Northern Ireland’s divided communities.
In 2012 the decision of Belfast City Council to reduce the number of days on which the Union flag is flown from City Hall sparked widespread protests and disorder.
DUP MP Sir Jeffrey Donaldson said it is “bizarre” that the UK Government is “only deciding in 2021 to fly the Union flag, the flag of our nation, on all Government buildings every day”.
“When I visit other nations around the world, flying the national flag on Government buildings is commonplace,” he said.
“The decision to exclude Northern Ireland at this stage is wrong and runs contrary to New Decade, New Approach which sought to align us with the rest of the UK when it came to the Union flag being flown on Government buildings.
“This is a matter we will be pressing the Government to address.”
Meanwhile Sir Jeffrey said the Northern Ireland Protocol, which governs post Brexit trade arrangements, is “deeply damaging” to the Union.
The mechanism has brought additional checks on goods arriving at the region’s ports from Great Britain, and has been dubbed a border in the Irish Sea.
“If the Government wanted to immediately improve the Union, they would start with the removal of the protocol,” the Lagan Valley MP said.