"We will get out of this crisis very soon," Ghannouchi told journalists after meeting UGTT Secretary General Hussein Abassi. "We accept the UGTT initiative in principle to begin the dialogue" with the opposition.
The UGTT trade union federation, which is mediating between Ennahda and its critics, has proposed the government step down and let a neutral interim cabinet prepare new elections. Ennahda had rejected this in the past but changed course this week.
Tunisia's opposition parties declined to comment immediately on Ghannouchi's statement.
Both the Islamists and the opposition agree on the need for new voting once work on a long-delayed new constitution is completed, which could happen in the next few months. But the opposition does not trust Ennahda to hold a free and fair vote.
Ennahda, which governs in coalition with two smaller secular parties, is under increasing pressure from the opposition over accusations that is imposing an Islamist agenda, failing to deal with violent Salafi Islamists and mismanaging the economy.
Tunisia voted on October 23, 2011 for a constituent assembly which was to write a new constitution within a year, a deadline it failed to keep because of protracted wrangling between the Islamists and the secular opposition parties.
Four months were spent on debate just about whether to mention sharia, the Islamic legal and moral code, in the constitution. Ennahda finally agreed to leave it out.