Sudan began exporting oil in 1999, and relief workers say that since then it has fuelled Africa's longest-running civil war.
The report says Sudanese Government troops, and militias allied to them, have killed or terrorised tens of thousands of civilians into leaving their homes to make way for foreign oil companies to explore and extract the new reserves.
Christian Aid's policy director, Mark Curtis, told the BBC that the companies needed to use their influence to send a strong signal to the Sudanese Government.
The country's oil revenues have grown to an estimated $400m a year, he added.
Sudan began exporting oil in 1999, and relief workers say that since then it has fuelled Africa's longest-running civil war.
The government had doubled its military budget since oil came on stream, the charity said, showing there was a direct correlation between oil revenue and the ability to wage war.
It also says infrastructure designed for the oil industry is being used by government forces fighting in the area.
Mr Curtis said oil companies from Malaysia, China, Canada and Sweden operated in Sudan.
And he accused oil giants BP, Shell and ExxonMobil of indirect involvement through their investment in two subsidiaries of China's state oil company, PetroChina and Sinopec.
However, the multinationals maintain that their funds are ring-fenced and can not be used for investment in Sudan.
Testimony
Christian Aid says the report is based on the testimony of people who fled the oil-rich areas.
It quotes displaced civilians as saying their villages were attacked by air before government troops burned down their homes and killed those unable to flee.
It says that in one area where prospecting has just begun, 48 villages have been burned and 55,000 people displaced over the past 12 months.
UN officials and diplomats in Sudan say it is extremely hard to verify the contents of the report because of the difficulty of visiting the area.
There has been no comment so far from the Sudanese authorities.