According to reports the suspects were aiding the groups running a smuggling racket from Hong Kong to China.
Sources said that the Indians were detained on Jan 8, before the arrest of the Chinese engineers in connection with the Balco chimney collapse case on Monday, Jan 11.
Ministry of external Affairs on Tuesday, Jan 12 had cited awareness of the detention of the Indians by Anti-Smuggling Bureau of Shenzhen Customs (China) Jan 8 and said that it had sought for a consular access to the detained Indians.
The access is expected to be granted on Wednesday, Jan 13.
"They are charged with illegal transportation of diamonds from Hong Kong to Shenzhen. On learning of this detention, our Embassy in Beijing immediately approached the Chinese authorities seeking consular access to the Indian nationals, as provided for, in a Memorandum of Understanding on consular matters of 2003," the statement by the Ministry of External Affairs said.
Foreign Minister Nirupama Rao said that the Beijing Embassy has been asked to submit report on the matter.
"I have asked our ambassador in Beijing for factual report on this matter," she said.
According to a Chinese daily, 21 Indians including 50 foreigners were arrested in a major crack-down by the Shenzen Customs officials against a local smuggling ring.