Only dialogue can resolve the crises in war-torn Syria and Libya, Tunisian civil groups honoured with this year's Nobel Peace Prize said Wednesday on the eve of the awards ceremony in Oslo.

The Tunisian National Dialogue Quartet was awarded the prestigious prize on October 9 for saving the country's transition to democracy at a sensitive moment in 2013 when the process was in danger of collapsing because of widespread social unrest.

"Arms can never be a solution, not in Syria nor in Libya. There is a need for dialogue and no blood and no fighters," Abdessatar Ben Moussa, head of Tunisia's Human Rights League, told reporters.

While the wave of Arab Spring uprisings has led to chaos in neighbouring Libya, Yemen and Syria, and to the return of repression in Egypt, Tunisia has been held up as a success story.

The country adopted a new constitution in January 2014 and held democratic elections at the end of last year.

"Tunisia is an exception so far in the Arab Spring countries but this doesn't mean that it may not be replicated in other countries," said Houcine Abassi, secretary general of the powerful Tunisian General Labour Union.

But almost five years after the overthrow of dictator Zine El Abidine Ben Ali, the jihadist threat weighs heavily over Tunisia's road to democracy.

After November 24 suicide attack targeted a bus carrying presidential guards, killing 12, officials enforced a night-time curfew in the capital Tunis, temporarily closed the Libyan border, and announced a state of emergency for the second time this year.

Last week, Amnesty International expressed concern over the subsequent wave of arrests and detentions by the security forces, saying it was "a troubling sign that the authorities are reverting to repressive and abusive measures."

"Freedom cannot accept any sort of sacrifice when it comes to human rights," said Ben Moussa.

"Basically terrorism feeds on the oppression of human rights."

The National Dialogue Quartet is made up of the Tunisian General Labour Union, the Confederation of Industry, Trade and Handicrafts, the Human Rights League and the Order of Lawyers.