Given that the maximum sentence on the witness tampering charge before the International Criminal Court is five years in prison, Bemba should be formally released some time after that hearing.
"In principle, Senator Jean-Pierre Bemba Gomba will return to the country in July," the spokesman for his Movement for the Liberation of Congo (MLC) party, Michel Koyakpa, told Reuters.
"This will first of all be to participate in the MLC congress, which will take place July 12-13 in Kinshasa," Koyakpa said, adding that Bemba would submit his candidacy for president later in July if selected as the party's nominee.
The government has said that Bemba has the right to return home but has offered mixed messages about whether he might face further criminal prosecution or be allowed to contest the presidential election.
Bemba is popular in western Congo and his return could give a jolt to a largely moribund opposition. But it could also further divide Kabila's opponents, several of whom are angling to succeed him.
Bemba came third in a rare nationwide opinion poll by New York University's Congo Research Group in March, behind opposition leaders Moise Katumbi, who is in exile in Europe due to myriad legal problems at home, and Felix Tshisekedi, the president of Congo's largest opposition party.
If Kabila does not try to stand himself, he is expected to annoint a successor to represent the ruling PPRD party. That person would benefit from the party's significant war chest and ties to state institutions.
Bemba finished runner-up to Kabila in a 2006 election that his supporters said was marred by fraud, triggering battles in the streets of Kinshasa between his militiamen and state security forces.