The two Swiss businessmen sentenced earlier this month to 16 months in jail by a Libyan court, are to leave the embassy on Tuesday to attend an appeal hearing.
The two men did not attend the original trial, at which they were convicted of visa irregularities and tax evasion.
Their lawyer, Salah Zahaf, told the AFP news agency on Monday that they would go to the court in person, and would return to the embassy afterwards.
He did not say whether they had been given any guarantees that they would not be arrested.
The two, Max Göldi and Rachid Hamdani, have spent much of their time in the Swiss embassy in Tripoli since they were prevented from leaving Libya in July 2008, shortly after one of the sons of Libyan leader Moammar Gaddafi, was detained by police in Geneva, along with his wife, on charges of mistreating two servants.
Göldi and Hamdani face further charges of doing business illegally in Libya.
swissinfo.ch and agencies