The Afghan president said he believed the majority of Taliban fighters were “definitively willing to seek peace”.
Mr Karzai also restated he would not stand for re-election in 2014 and would counsel his brother Qayyum, who has been touted as a potential candidate, not to run either.
“There have been contacts between the US government and the Taliban, there have been contacts between the Afghan government and the Taliban, and there have been some contacts that we have made, all of us together, including the Taliban,” Mr Karzai told the Wall Street Journal.
The Taliban movement has publicly refused to talk with Mr Karzai’s government, denouncing him as a foreign puppet.
Mr Karzai said such refusals were only “statements” and his government was in fact “talking to the senior-most of them. Contacts at different levels, official, personal, all sorts.”
Jonathan Baume, general secretary of the First Division Association (FDA) which represents senior civil servants, said pay among the highest-ranking staff needed to be more “transparent”.
His comments come after it was disclosed that more than 25 senior Department of Health officials have had their salaries paid to limited companies, enabling them to reduce their tax bill.
However, Mr Baume said he believed such arrangements had allowed the Government to pay senior figures less and that cleaning up the system would mean salaries would have to rise.
He said the problem stemmed from the last years of the Labour government when ministers wanted to attract top individuals working in the private sector but could not offer them salaries which compared favourably.
The men were specifically targeting Israel diplomats and planned to plant “sticky” bombs on their vehicles, the same method used in attack on an Israeli diplomat in New Delhi and a foiled plot in Tibilisi on Monday.
Police General Prewpan Dhamapong said Thai authorities “know for certain that [the intended target] was Israeli diplomats. The issue was about individuals and the targets were specific. This was something personal.”
Thailand is to seek the extradition from Malaysia of an Iranian man who was part of the plot.
Immigration authorities in Kuala Lumpur arrested the man Masoud Sedaghat Zadeh, 31, on unspecified charges on Wednesday as he tried to board a flight to Iran.