The explosion on Saturday comes days after similar attacks rocked the country's northwest.
Irfuanullah Khan, a police official, said an explosive-laden car hit a police checkpoint on the outskirts of the city and that the dead included some police officers.
Liaqat Ali Khan, the Peshawar police chief, told the AFP news agency: "There are two policemen among the dead."
Officials say the death toll is likely to rise.
Anti-government Taliban fighters have struck numerous times in Pakistan in recent weeks, killing more than 300 civilians and soldiers.
The attacks appear to be aimed at weakening the government's resolve to continue its military operation in South Waziristan, the Taliban's main bastion, on the border with Afghanistan.
Last month, a car bomb ripped through a crowded grocery market in the centre of Peshawar, killing more than 100 people, mainly women and children.
The Taliban said it did not carry out the October attack in Peshawar that was described as the deadliest in the country in two years.
A truck bombing at the regional headquarters of Pakistan's national intelligence agency killed at least 10 people in Peshawar on Friday.
Source: Al Jazeera (English)