"Nine people were killed and several others were injured in the blast", a police source said.
The blast was believed to have targeted Wardak's vehicle. The Afghan lawmaker is said to have survived the incident, according to law enforcement sources. No organisation has claimed responsibility for the incident so far.
The explosion is yet another episode in a recent string of terrorist attacks across the country.
Later in the day, the Afghan interior minister, Massoud Andarabi, confirmed that nine people were killed and 20 others suffered injuries in the explosion, as reported by the country's TOLOnews broadcaster.
Throughout Sunday, several other bombs were detonated across Afghanistan. In Jalalabad, a device exploded near a police vehicle at roughly 10:00 local time (05:30 GMT), leaving two law enforcement officers injured, Farid Khan, a police spokesman in Nangarhar province, said.
One person has died in the northern province of Badakhshan after a roadside improvised explosive device detonated in the Baharak district, a regional police spokesman said in a statement.
A car bomb also exploded in the town of Pol-e-Alam, the capital of Logar province, regional police chief Shapoor Ahmadzai said. The blast reportedly left one civilian with injuries.
A suicide bomber also attempted to launch an attack on Afghan National Army (ANA) forces in the Nawa-I-Barakzayi district of Helmand province earlier in the day, the Afghan Ministry of Defense said.
"He was identified and eliminated by the ANA before he could reach his target. Unfortunately, 2 ANA members have received minor injuries as a result of the incident", the ministry wrote on Twitter.
According to the Afghan Interior Ministry, 35 suicide attacks and 507 bomb blasts, conducted by the Taliban have killed more than 480 civilians and wounded over 1,000 in the last three months. At least 15 were killed and 20 others injured in Friday's bomb attack in Ghazni alone.
The escalating violence in Afghanistan is taking place despite both the government and the Taliban having been engaged in peace negotiations in the Qatari capital of Doha since September.