A letter sent to Lebanese President Michel Suleiman from U.N. Secretary-General Ban Ki-moon asks for comments regarding plans to extend the tribunal's mandate by three years.
"The requested observations are over the three-year period only, not over the principle of renewal," a senior political leader told The Daily Star newspaper in Beirut on condition of anonymity.
The tribunal is investigating the 2005 assassination of former Prime Minister Rafik Hariri. Four members of Hezbollah are the tribunal's top suspects in the slaying.
Lebanese Prime Minister Najib Mikati suspended Cabinet sessions to avoid political conflicts over the mandate for the Special Tribunal for Lebanon. Lawmakers with Hezbollah are among the members of Mikati's ruling coalition.
Naim Qassem, Hezbollah's deputy secretary-general, said last weekend that Lebanon, meanwhile, wouldn't be a platform for attacks on other countries in the region.
A salute to the Lebanese army protecting the Lebanese borders, especially in the northern areas, so that Lebanon does not become a thorn in Syria's side," he was quoted by The Daily Star as saying.