Former England cricketer Phil Edmonds and colleagues in the White Nile oil firm are in Kenya to meet leaders from southern Sudan about drilling rights.
The SPLM is keen to take control of the oil business in its territory
The ex-rebel leaders running southern Sudan have rescinded rights to oil exploration in territory they control.
The Sudan People's Liberation Movement has handed over part of an exploration block claimed by France's Total to White Nile, sending its shares soaring.
But White Nile shares are now suspended in London until a prospectus is issued.
White Nile is listed on the Alternative Investment Market (AIM), which is calling for a detailed document outlining the fine details of the proposed deal with the southern Sudan leadership.
Mr Edmonds has been accompanied on his trip by White Nile partner Andrew Groves, and representatives of Exploration Consultants Limited, to draw up a "contractor's licence".
"They are meeting the southern Sudan leadership council to draw up a document which makes clear how money is being spent on exploration, how contractors will be used, and also looking at things such as social programmes and reconstruction," a White Nile spokesman told BBC News.
The firm started negotiations two years' ago with the Sudan People's Liberation Movement (SPLM), which, following peace talks in January, now forms a government-in-waiting for southern Sudan.
In February, White Nile signed a deal with a company called Nile Petroleum, which was set up by the southern Sudanese leadership to look after its oil interests.
White Nile will be given a 60% stake in a 67,000km exploration area known as Block Ba, which may hold as much as six billion barrels of oil.
And, in return Nile Petroleum will be given 155 million shares in White Nile.
"This gives the Southern Sudanese more control over their own destiny," said the White Nile spokesman, adding that it would also provide Nile Petroleum with a quicker return than under a conventional exploration deal.
'Not an issue'
But Total insisted its own rights - agreed with Khartoum in 1980, before the civil war between the mainly Arab north and the Christian south started - remained intact.
The White Nile spokesman said: "The Total claims are not really an issue for White Nile now. Khartoum does not control the land.
"The Nile Petroleum agreement superseded that deal. Southern Sudan and Nile Petroleum are very happy with the new agreement, it is a very positive thing."
The remaining 40% of the Block Ba is retained by Nile Petroleum.