SINGAPORE - A 30-year-old man has been arrested in a vandalism case in which racial slurs were scrawled at a sheltered walkway near Aljunied MRT station.

It is not clear when the words, which targeted the Malay and Muslim community, first surfaced, although the police said they were alerted to an incident of vandalism at Lorong 25 Geylang at 8.15am on Monday (Jan 7).

The man was arrested on the same day following police investigations.

The offensive words were scribbled on three poles at the walkway, and on a concrete pillar supporting the nearby MRT track next to Geylang Methodist Primary and Secondary Schools.

The Land Transport Authority, which oversees the upkeep of the structures, has worked with its maintenance contractors to remove the graffiti.

Local novelist Balli Kaur Jaswal expressed concerns about the derogatory words on her Facebook page on Friday morning.

She said that she was showing a friend, who was a foreigner, around the area on Friday morning when she noticed the graffiti.

"I was really surprised, I saw one at first and thought that I had read it wrongly, but I realised there were three in a row; it hit me then that it was quite deliberate that someone was writing these things to be seen, there is a large Muslim community in the area," said Ms Jaswal, 35, who spoke to ST over the phone.

What concerned her most was that young students from nearby schools could easily read the graffiti on their way to and from school, she added.

"If you put yourself in the shoes of a young Muslim or Malay student, the words would be very hurtful, you'd feel like you're being targeted and insulted, and that would make a real negative impact for someone who's just on their way to school," Ms Jaswal said, describing the vandalism as a cowardly and sickening act.

A passer-by, who said he worked nearby and declined to be named, said he had alerted the police to the graffiti. He said he did so after spotting a young schoolboy looking at the words.

The man also said he was "offended and disgusted" by the vandalism.

"You shouldn't do to others, what you don't want done to you," he said.

Ms Rasyidah, 19, a recent graduate of the Madrasah Aljunied Al-Islamiah school who saw the graffiti for the first time on Friday, hoped that it would be cleaned up soon.

"I'm not personally offended by it, but others might be," said Ms Rasyidah.

Criminal lawyer Sunil Sudheesan said that the perpetrator could face charges for vandalism and for sedition.

Police are investigating.

If convicted, vandals can be fined up to $2,000 or jailed for up to three years and given eight strokes of the cane. For sedition, first-time offenders could be fined up to $5,000 and jailed for three years.