A contingent of Chinese troops entered the north-eastern Indian state of Arunachal Pradesh last week and camped there for four days, media reports say.
Peoples Liberation Army soldiers entered India on 11 August and left on 15 August, the Press Trust of India quoted defence sources as saying.
India's foreign ministry played down the report. Beijing is yet to comment.
The neighbours, who fought a brief war in 1962, dispute several Himalayan border areas.
Earlier in April, India asked China to withdraw troops it said had moved into disputed territory near the two countries' de facto border in the Ladakh region.
Both India and China claim Arunachal Pradesh and the Aksai Chin area of Ladakh in their entirety.
They have held numerous rounds of border talks, but all have been unsuccessful so far and tensions flare up from time to time.
The latest incident took place in the Chaglagam area. Reports said the Chinese troops left after a meeting with the Indian border personnel.
Indian authorities described the reports of the incursion as "non-events".
"We don't take up non-events in diplomatic practice. What has happened or not is up to sentinels of our borders to answer. They know the factual position on this and I think they have answered that," external affairs ministry spokesman Syed Akbaruddin told reporters in Delhi.
"There has been a rebuttal by the army on this and we don't want to to go beyond that," he added.