About 30 stray cats have invaded the Senoko Power Station in Sembawang after neighbouring factories and warehouses shut amid Covid-19.

The influx of unsterilised cats at the protected site has raised concerns that it may lead to an increase in the feline population and fights with the sterilised cats that now call the station home.

Ms Cindy Lim, senior vice-president and head of legal and compliance at Senoko Energy, said there were 10 resident cats at the power station, which employees - including herself - regularly feed.

"That's likely why stray cats from the surrounding industrial area, such as the food processing factories, flocked to Senoko Power Station when those places closed - for food and shelter," she told The Sunday Times.

While the resident cats were sterilised by the Cat Welfare Society (CWS) about two years ago, the stray cats that flocked to the power station in late August are not neutered. Ms Lim said: "I noticed a few pregnant cats among the new strays... if left unchecked, cat numbers can easily double or triple in a few months."

Around 20 cats were spotted roaming around a busy part of the site where welding and machine-cutting works were carried out.

"There's heavy machinery and bulldozers at the tight compound they're at. Two of the cats have suffered crush injuries that resulted in limb amputation," she added.

Mr Graeme York, chief executive and president of Senoko Energy, told The Sunday Times that the company engaged a professional cat trapper who works with CWS. Seventeen cats - 12 kittens and five adult cats - were trapped on Sept 19. "The adult cats were sterilised under CWS' stray cat sterilisation programme and returned to the power station," he said.

The kittens were placed in foster care and put up for adoption; Ms Lim fostered two. Ten of the kittens have been adopted.

Ms Lim and Mr York plan to schedule another session to trap and neuter 12 more cats at the power station next month.

Said Mr York, a self-professed animal lover: "I'm not against having a small population of cats at our site... but it is important they are neutered so the population doesn't grow out of control."

CWS president Thenuga Vijakumar said that the number of cats in industrial areas will multiply rapidly if they are not sterilised.

"This is a huge problem in industrial and restricted areas, as permission is often needed to enter premises to trap the cats. We often get turned down by companies," she said.

Ms Thenuga added that having many unsterilised cats will result in caterwauling, scent-marking with urine and territorial fights. Unsterilised cats can bring these issues to neighbouring cat communities that have been sterilised.

"Covid-19 has also caused great disruption... feeders have decreased in harder-to-reach industrial areas. So they are not able to react swiftly to new unsterilised cats and rampant breeding follows," she said.