Sections of the world's first magnetic levitation train line are reported to be sinking.
The Maglev train link connects the centre of Shanghai to the airport
But the Transrapid consortium behind Shanghai's maglev train said it was dealing with the issue.
"The designers of the maglev had foreseen the problem and had taken effective, sufficient measures," government spokesman Jiao Yang told China's official news agency Xinhua.
The Transrapid International consortium, based in Germany, supplied the technology for the maglev rail link.
Floats on air, held by powerful opposing magnets
Speed: more than 430 km/h (260mph)
In a recent statement, the consortium insisted that normal "settling" could be compensated by minor readjustments without interrupting passenger service.
It added that there was no information the "settling" had exceeded the normal degree associated with structures of this type.
Subsidence is not the only problem facing the backers of the $1.2bn maglev project.
Fares were slashed by half in mid-April, to appeal to passengers previously put off by high prices and an infrequent service.
The magnetic-levitation, or maglev, train carries passengers on a magnetic cushion above the tracks.
The train travels at speeds of over 400km/h (250mph) - completing the 30km (19 mile) journey from the city to the airport in just eight minutes.