Cracks can be found on the concrete supports of train tracks along the Tsuen Wan Line at Admiralty station, the MTR Corporation has admitted, but said these did not affect railway operations.
The company was responding after a Chinese-language newspaper observed more than 30 cracks on the concrete and suggested they might have been caused by construction work for the South Island Line.
Minor cracks and imperfections on the surface of concrete slabs were normal in functioning railways, the MTR Corp said.
"It is a problem in the appearance and is not related to structural safety," an MTR spokesman said yesterday. "We'll see if it requires any maintenance."
Professor Lo Kok-keung, of Polytechnic University's mechanical engineering department, said such cracks would not usually cause problems unless they were left unfixed for a long time and deepened, allowing water to seep inside.
Under that scenario, the metal structures underneath would rust, affecting the structure of the track, Lo said.
He said it was normal for vibrations from the trains - and for the excavation works - to cause the cracks that Oriental Daily News had reported on.
The MTR Corp said it had been using precise monitoring devices to ensure the excavation in Admiralty would not affect surrounding structures.
The station was undergoing five-yearly checks and would make the necessary repairs, the company said. It said the excavation had not triggered any problems that affected railway safety.
The South Island Line, to link Southern district to the MTR network, is to open next year. But the Highways Department says work at Admiralty station has "lagged behind considerably".
Meanwhile, MTR staff unions called for an average pay rise of at least 6.5 per cent this year.
The workload had risen with increasing train frequencies, four of the unions said, based on feedback from about 1,500 of their members. Recent glitches in services had hit staff morale and many veterans were planning to leave, they said.
The unions wanted higher starting salaries for frontline workers and priority for suitable contract labour. The company told them it would respond some time next month, they said.