The tourists would decide in 10 days' time whether to play two One-day Internationals in the southern city, which has a history of religious and ethnic violence, Pakistan Cricket Board (PCB) official Saleem Altaf said on Tuesday.
"England have refused to play a five-day Test in Karachi and they will reply in 10 days to our proposal to play two back-to-back One day Internationals there," Altaf said in the eastern city of Lahore.
Two English experts have spent the last week assessing security at various grounds and a two-member England and Wales Cricket Board (ECB) delegation arrived in Pakistan on July 3.
The England team's provisional schedule on the tour from October 25 until December 22 had included three Tests in Karachi, Faisalabad and Lahore.
It also included One-day games in Lahore, Rawalpindi and Karachi. The northwestern border city of Peshawar has already been ruled out due to its close proximity to Afghanistan.
Karachi has been rocked by a series of deadly shootings as well as a suicide bombing at a mosque and the burning down of a KFC restaurant in recent months.
In the aftermath of the September 11 attacks, foreign teams like Australia and the West Indies have refused to play in Pakistan over security fears.
Karachi has been rejected as a Test venue by South Africa and India since a bomb blast outside the New Zealand's team hotel in May 2002 killed 14 people including 11 French naval engineers.
The tour will be England's first since 2000 when Nasser Hussain's team won their first series in Pakistan for 39 years. England won a Test in Karachi on that tour.