The plaque honoured the place of Trooper Sing's death, which occurred on on May 19, 1943, at a since-demolished boarding house at 304 Montague Road, West End.

Building owner Orfeo Lazzareitti told Fairfax Media on Wednesday he "had no idea" why a sign company employed by real estate agent Nick Zervos had covered the two historical plaques, installed by the Military Historical Society of Australia in 1993 to mark 50 years since Trooper Sing's death.

Amateur historian Merv Bonnell highlighted what he called a "disrespectful act" on Tuesday after he went to pay his respects to Trooper Sing. On Thursday, he was delighted the sign had been shifted.

"It's a good result," he said.

"It was a very stupid thing to have just put it over that.

"It's important because he is one of our unsung heroes that never gets talked about a real lot."

William Carroll from the Queensland Military Historical Society said he was happy to learn the sign had been removed.

"I've just had a call about it," he said. "It's a good thing that the sign has been taken down."

EARLIER

They say Lest We Forget, at least on Anzac Day.

Other days, we just forget.

Last week, a sign company working for a real estate agent in Brisbane screwed a 'for lease' sign over the top of a plaque to Australia's most famous Gallipoli sniper, World War I veteran Billy Sing.

The building's owner wanted to lease out a warehouse and two car parks in the buildingand asked real estate agent Nick Zervos to find customers.

Mr Zervos hired a sign company, which screwed attached the sign over the brass plaque honouring Trooper Sing.

Trooper Sing was a part-Chinese Australian serviceman who was best known as "The Assassin of Gallipoli" and Australia's crack shot as a sniper during the Gallipoli campaign.

He was credited with 119 kills, but according to General William Birdwood, he had at least 201 unconfirmed kills. Trooper Sing's commanding officer, Major Stephen Midgely, always said he killed 300 Turks at Gallipoli.

When his military career ended after being wounded by rifle fire and by gas poisoning, Trooper Sing worked as a shearer, gold miner and finally a labourer.

He died alone in a now-demolished boarding house at 304 Montague Road at West End on May 19, 1943, and was buried in Lutwyche War Cemetery.

Trooper Sing's grave was originally unrecognised until the RSL arranged for a large monument to be built in 2005.

Eventually, Queensland's Military Historical Society also placed a bronze plaque on the wall at 304 Montague Road to honour Trooper Sing's final days.

The plaque was spotted earlier this week by amateur historian and firefighter Merv Bonnell.

"The boarding house was knocked down, but they put the plaque up on the wall of building that is now on the site, so the plaque is still there, but it is covered over by this for lease sign," he said.

Mr Bonnell said he was horrified such little respect had been shown towards Trooper Sing.

"I would like to see that bloody sign taken off. I think it's bloody rude," he said.

"It's just disrespectful, if you know what I mean."

Mr Bonnell had read books about Trooper Sing and had read about the plaque at West End.

"I just wanted to see it and to take a photograph," he said.

Mr Bonnell, 55, said the plaque must be uncovered and remain on any building that is built on the site.

Mr Zervos said he had been made aware of the oversight by the sign company, which erected the signs on behalf of the building owner.

He said he had contacted the company "three times since last Friday" to move the sign to let Trooper Sing's plaque be seen.

"The sign company has been notified and we will have it moved," Mr Zervos said.

"It should be within the next day or so. The sign is not a permanent sign and it is being removed.

"It is an oversight, that's all."