The men had been seized along with four other Chinese nationals and two Sudanese drivers near the disputed oil region of Abyei on October 19, apparently by tribe members seeking greater oil wealth.
Ali al-Sadiq, a foreign ministry spokesman, said on Monday that five of the abducted workers had been killed and two injured as they escaped. Two more men are still being held hostage.
Al-Sadiq said: "Fiver were murdered. Two were able to escape with minor injuries."
The Chinese team had been working for the China National Petroleum Corporation (CNPC) at the time of their capture.
The oilfield is run by the Greater Nile Petroleum Operating Company (GNPOC), a consortium of four oil companies from China, India, Malaysia and Sudan.
The kidnappers released one of the Sudanese drivers shortly after the men were abducted.
An unidentified diplomatic source said shortly after the attack that members of the Arab Messeria tribe had carried out the abduction in an attempt to win a greater share of the region's oil revenue.
However, al-Sadiq said the kidnappers were members of a Darfur group called the Justice and Equality Movement (Jem).
The abduction is the third such incident over the past year in the region, the source of a large part of Sudan's oil wealth.
