"We found the request submitted by the organisers fulfilled conditions set by the interior ministry and accordingly we issued the necessary licence," interior ministry spokesman Colonel Adel al-Hashash told a news conference.
The ministry has insisted the protest be peaceful, he said.
Authorities banned two previous protests on October 21 and November 4 but the opposition went ahead and staged processions which turned violent.
More than 150 protesters and 24 policemen were slightly injured when riot police used teargas and stun grenades to disperse the two rallies.
Opposition activists, whose parties have called for an election boycott, said on Twitter that they had received the permit and will go ahead with the protest on Friday, a day before the polls.
The Islamist, nationalist and liberal opposition has been protesting against the government for unilaterally amending the electoral law even after the top court in the oil-rich Gulf state ruled the legislation was in line with the constitution.
The opposition charges that the amendment clears the way for the election of a pro-government parliament.