Responding to earlier criticism, the electoral commission said on Wednesday that the allegations were baseless.
Mr Lisu is one of 14 candidates to challenge President John Magufuli, whose party he has led the country for decades.
Admired for some of his courageous approaches like his fight against corruption, Magufuli’s first term was overshadowed by claims by human rights groups that he limited democratic freedoms.
The few results published so far have put Magufuli ahead of the all candidates.
Maalim Seif Sharif, the main opposition candidate for president of the semi-autonomous archipelago of Zanzibar, was arrested shortly after the drilling was after he criticised the conduct of the elections alleging rigging and called for mass protests.
On Wednesday, the head of the National Electoral Commission denied allegations of election fraud. Semistocles Kaijage said the allegations of ballot forgery were baseless.
On Tuesday and Wednesday, internet users reported that WhatsApp and Twitter were blocked, among other things.
Voting itself was calm and peaceful on the in the country except reports of violence in Zanzibar on Tuesday.
Tundu Lissu claims many of his party’s agents were prevented from entering the voting centres for several hours when the fraud took place.
He also called on the international community to condemn the elections and sanction those accused of obstructing the election process.
The results of the presidential election in 17 of the more than 260 constituencies published on the Electoral Commission’s website represent a huge advantage for President Magufuli.
In many of them, he received at least 80% of the votes. In one of them, Misungwi, he received nearly 99% of the votes.