A shopping mall owner has apologised for putting up a sign banning construction workers from its toilets and threatening them with a $107 fine for unauthorised use.

Facebook user Martha Tara Lee took a photo of the warning - taken at the new Marina One centre - and posted it online yesterday, saying she was "shocked".

The sign read: "A penalty of $107.00 (incl. of GST) will be imposed for non-compliance and unauthorised use of toilets at level 1 and 2."

It added that workers should use the loos at Basement 2.

The mall's owner, M+S, apologised for "any concern the sign may have caused" yesterday evening, following queries from The Straits Times.

It added that it was industry practice to have designated toilets for workers at newly completed developments.

M+S explained: "This practice ensures that there isn't any confusion for those needing to use the toilets, who may think that contractors are there to fix an issue. It also keeps out any construction dust from these facilities, for the comfort of the users."

Ms Lee said she complained about the sign to the building's management and added of the fine: "What percentage of their daily wage is this?"

Some Facebook users took the sign to be a form of discrimination, while other users pointed out that workers could tread concrete and dirt into the bathrooms.

A Facebook user called Benuel Ganesan wrote: "Would have understood the sentiment if they had instead said, 'If you are working at a nearby construction site and need to wash up - please use the toilet on Basement 2 which has been reserved for you. We appreciate and thank you for your consideration in helping to keep toilets clean for the benefit of all.'"

M+S is a joint venture between Khazanah Nasional and Temasek, which are investment companies of Malaysia and Singapore respectively.

The Marina Bay development, which includes commercial, retail and residential components, was completed late last year. But the spokesman said that workers are still present to fix defects.

M+S said the sign has been reworded, deleting the threat of a fine. The spokesman added that no worker has been fined so far, and that workers and contractors were earlier informed to use the designated toilets.