The Deputy First Minister of Northern Ireland Martin McGuiness has urged Irish republican dissidents to end their violence on the 20th anniversary of the ceasefire by the Irish Republican Army.

McGuiness, a former IRA commander, said the groups should "take that same step into politics and away from conflict" and that there could be "no return to the violence and repression that scarred this society for so long".

"In 1994, dialogue offered the only way out of perpetual conflict and Irish republicans entered that dialogue confidently," he said in a speech in Derry, marking the anniversary.

"Successive agreements supported by the vast majority of the Irish people have removed any rationale for armed struggle and have put in place peaceful and democratic alternatives," he said on Sunday.

McGuiness criticised the Democratic Unionist Party, with which his Sinn Fein party reached a power sharing agreement in 2007.

"The absence of dialogue and a commitment to dialogue as the way to overcome disagreements is at the heart of the growing difficulties we are now facing in the peace process across a range of key issues," he said.

He said the "real threat to the political institutions is stagnation and the absence of progress".

"I have personally tried to understand and reach out to the unionist population not least in my engagements with Queen Elizabeth," he said.

"But reconciliation is not a one-way street - unionist leaders need to engage in similar initiatives. So there is an enormous onus on those who recognise the enormous progress we have made, and continue to make, since the IRA cessation in 1994 to make their voices heard."