Opposition parties in the Democratic Republic of Congo have rejected an offer of "national consultations" made by President Joseph Kabila, they said in a joint statement released in Kinshasa.

The political opposition said it was "not concerned" in any talks that failed to take account of "the social situation" of the people, as well as "the problem of the legitimacy of power, human rights violations, ... the looting and selling off of natural resources and (the issue) of ill-gotten gains," said the document released Monday and signed by 60 members of parliament and other figures.

The main opposition party in the vast central African country, the Union for Democracy and Social Progress (UPDS), did not sign the declaration, but has several times said that it rejects Kabila's proposal, made after a cabinet meeting last week.

The parliamentary wing of the UDPS has turned down "a biased approach" and "a sham of dialogue". The party has contested Kabila's legitimacy in power since elections late in 2011, which the US-based NGO Carter Center described as lacking in credibility.

Kabila's government has worked on the proposal of round-table talks for several months, arguing that participants should "reflect on the ways and means to bring a lasting and global response to the crisis afflicting Congolese institutions and parties".

In their statement, the opposition responded that they asked for a "national political dialogue" in the wake of the troubled 2011 elections and argued that the effects of the flawed poll were "worsened by the creeping rot in the state".

Opposition parties also noted that the government last February committed itself at talks in Addis Ababa to "organise a transparent and inclusive political dialogue among all concerned Congolese parties".