Tthe official requesting anonymity said that they have disappeared in a suspected attempt to remain in Britain.
Three of them, judoka Chamila Dilani, her manager Asela de Silva, and wrestler Shanith Chathuranga had disappeared last week.
That prompted the Sri Lankan officials to file a police complaint.
Another seven have vanished since then, the official reported, without identifying them.
“We suspect they want to remain in the UK, possibly to get employment," official said.
Sri Lankan management had held the passports of the 160 member contingent to ensure their return to home but they failed to deter few members from leaving.
Sri Lankan official told AFP that the British police had located the first three members who had disappeared, but as they had not violated local laws and held visas valid for six months, no action was taken.
"In fact, the police got us to return the passports that we were holding as a deterrent against defections," the official said. The police have not told the officials about their whereabouts.
Britain's West Midlands police force, which covers Birmingham, said it was looking into reports of six Sri Lankans going missing from the Games, and said "enquiries continue to ensure they are safe and well".
The police force declined to comment further, including on the claim of there being 10 missing people in total, and the UK interior ministry also refused to comment.
Sri Lankan athletes have won one silver and three bronze medals at the Games as of Sunday evening.
This is not the first time Sri Lankan athletes have been reported missing from international events. There have been recurring incidents of such nature in the past too.
In October at Oslo last year, during a world championship tournament Sri Lanka's wrestling manager abandoned his team and disappeared.
During the 2014 Asian Games in South Korea, two Sri Lankan athletes made a run for it and were not found.
A similar incident happened in 2004, when Sri Lanka did not even have a national handball team, a 23-member group pretending to represent the country conned their way to a tournament in Germany and disappeared.
With inputs from AFP.
