At a gathering late on Monday Hariri called for calm, saying Lebanon should not fear "any political noise, which we hope to calm down and turn into calm speech, and start democratic dialogue".On Saturday, he said he wanted to know who killed his father but at the same time he wanted stability. "Dialogue cannot succeed with the accusations of treason and with repeated calls for tests of patriotism and nationalism," Hariri said.
Hezbollah, which fought Israel to stalemate in a 2006 war, is determined to deflect any blame for the 2005 assassination.
Hariri's remarks came before a scheduled session of "national dialogue" on Thursday in which rival leaders are trying to agree the country's defence strategy towards Israel.
Political sources said the tribunal was not on the agenda but it was very likely to be brought up during discussions.
The first national dialogue session was held in September 2008 after a Qatari-mediated deal ended an 18-month political crisis which led to a street fighting between Hezbollah and supporters of the pro-Western Hariri which took the country to the brink of renewed civil war.
The fighting broke out when the government tried to shut down a telephone network operated by Hezbollah, which called the move a declaration of war. Some analysts warned that such a scenario could be repeated if Hezbollah figures are indicted.
Hariri formed a national unity government last year which includes Hezbollah ministers. Analysts say if the tribunal does indict Hezbollah members, the group, together with Shi'ite and Christian allies, could decide to collapse the government.
Assafir newspaper said on Tuesday Hariri and Nasrallah's assistant Hussein Khalil held a late night meeting on Sunday. It quoted sources describing the meeting as "positive and very useful".
The Hariri murder triggered an international outcry and led to the withdrawal of Syrian troops from Lebanon in April 2005 after a deployment of almost three decades.
The killing has been widely blamed on Syria, but Damascus has consistently denied involvement.