Defence officials in Pakistan say they are considering demanding millions of dollars in annual taxes and charges on NATO trucks and fuel tankers passing through Pakistan en route to Afghanistan.
Officials say the charges might include tax on fuel, port and storages fees.
The supply route through Pakistan was closed after 24 soldiers were killed in a NATO air strike on two border posts on 26 November.
As a result, thousands of tankers are now stranded.
The BBC reports NATO forces in Afghanistan rely significantly on overland supply routes from the port of Karachi, which enter Afghanistan through the Khyber Pass.
On Sunday, Prime Minister Yousuf Raza Gilani told the BBC that Pakistan may continue its blocking of the convoys for several weeks.
On the same day, gunmen attacked tankers stranded in the province of Balochistan for the second time in four days. Seven tankers were destroyed.
