The Saltire usually flies over Montrose Town House in Angus but it was hoped to replace it on September 3 to mark Merchant Navy Day, which also pays tribute to the work of its present day seafarers.
Councillor Bill Duff (SNP), who represents Montrose, has been accused of trying to politicise the memorial after claiming the flag change was a ‘unionist stunt’.
The councillor ran a poll on his own Facebook page to gauge public opinion on a temporary flag change.
He then claimed the majority of people living in Montrose backed his view that “Scotland’s flag should fly on Montrose Town House” rather than the Red Ensign, which carries a Union Flag in the top left corner.
In a post on Twitter, he added: “There was a ploy afoot by Angus Councils ruling unionist coalition to haul down the Saltire and replace it with the Red Ensign to celebrate merchant navy day.
“My online survey showed 70% of Montrosians backed my views that the Scotland’s flag should fly on Montrose Town House.”
Merchant Navy Day is on the Scottish Government’s official list of flag-flying days.
Councillor Duff said there were “plenty of flagpoles” at the harbour where the Red Ensign could be flown.
After fielding a number of criticisms on Twitter, he added: “My constituents support my stance. The Saltire should fly from the main Council office in Montrose.
“I have no objection to other organisations flying their flags from other locations in the town.”
The Red Ensign flew in Montrose town centre last year on Merchant Navy Day with Councillor Duff claiming he received complaints from constituents over the flag change.
The flag was first flown in Forfar in Angus on September 3 2015 with the then Provost approving the change, which the local authority said was a civic - rather than political - matter.
The following year, the flag was moved to Arbroath following calls from a councillor in the seaside town with an arrangement then made to share the flag on alternate years with Montrose.
This year, the flag will again be flown in Arbroath with a ceremony to honour those who lost their lives in the Merchant Navy to be held down by the harbour.
Councillor Ron Sturrock (Conservative) put in a request with Angus Council for the flag to also be flown in Montrose this year.
He said: “Merchant Navy Day started in 2000 and September 3 was designated the date to reflect the date that World War Two was declared.
“The day is to symbolise all the merchant ships and merchant seamen that were lost during World War Two.
“Last year, the Merchant Navy Ensign was raised in Montrose and there was no negative feedback.
“Merchant Navy Day goes across all of the political spectrum and was meant to be a memorial day.
“With Montrose being the main port of Angus it was appropriate to mark our long association with the sea, which of course we still have.”
He described Councillor Duff’s comments as “unfortunate”.
Councillor Sturrock confirmed he asked for the ensign to be flow in Montrose this year but said he accepted that it was Arbroath’s turn to mark Merchant Navy Day.
The Red Ensign will be flown at Montrose Harbour on September 3 as the port celebrates a major redevelopment as well as its 525th anniversary.
This is the fourth year running that Seafarers UK is campaigning for the Red Ensign to be flown on civic buildings and landmark flag poles.
It said hundreds of flag-hoisting ceremonies will be organised this year.
A spokesman from the charity, which supports the maritime community, said: “Merchant Navy Day is on the Scottish Government’s official list of flag-flying days so it is very surprising that an individual councillor has a problem with it.
“All we are asking is for the Merchant Navy to be remembered on one day of the year.”