The main militant group in Nigeria's Niger Delta says it is willing to stop its violent campaign only if the new government frees its jailed kinsmen.
The militants' activities have led a 25% cut in oil production
Newly sworn-in President Umaru Yar'Adua has said the crisis in the oil-rich region will be his priority and has called for a ceasefire.
But the Movement for the Emancipation of the Niger Delta said he must show "genuine willingness" for dialogue.
The government must prepare for more violence if it fails to act, Mend said.
The militants have waged a sabotage campaign for more than a year in the under-developed region, including kidnapping dozens of foreign oil workers.
The activities of the militants have led to a more than 25% cut in oil production.
Criminal gangs in the region have used similar tactics to obtain ransoms for the release of captives.
Mend said that people were tired of words and wanted urgent action to end their impoverishment.
"Only time will tell if Mr Yar'Adua is not just another politician," Mend leader Jomo Gbomo said in an email to the media.
"The most important requirement of the Niger Delta people is justice. Genuine negotiations towards a just resolution are sufficient hope for the people of the Delta."
The BBC's Abdullahi Kaura in the Niger Delta says the militants want to make it clear to Mr Yar'Adua that they are standing firm.
Mend militants have always demanded the release of a militant leader Mujahid Dokubo-Asari, who is charged with treason, and former Bayelsa State governor Diepreye Alamieseigha, who standing trial for alleged money laundering.
Analysts say putting an end to the Niger Delta violence will be a slow and frustrating as hostage taking has become a very profitable business and the proliferation of arms in the region all combine to make the militants very powerful.
Although Mend appears to be the most prominent militant group in the region, analysts say there are other copycat criminal gangs that may not be interested in negotiations with the government.
Some of the militants are also believed to be involved in "bunkering", a term used to describe the breaking of pipelines and stealing fuel which is then sold illegally.
Insiders say it would be difficult for the militants to willingly give up this lucrative lifestyle.
Although Nigeria's oil money comes from the Niger Delta, the majority of the region's people remain deeply impoverished.
Nigeria is Africa's largest oil producer and fifth largest supplier of crude to the US.