The overture comes ahead of demonstrations the opposition has called for on Monday to protest against the poll's results.
Magufuli's main challenger, the Chadema party candidate Tundu Lissu, won only 13 percent of the vote.
Zanzibar and mainland Tanzania are due to hold elections for president, lawmakers and local governments on Wednesday.
A local Watchdog says the election process is already marred with irregularities, yet President John Magufuli is likely to win
Membe has denied any wrongdoing and has said he was kicked out of the party for wanting to run for president.