But Sheikh Mohammed bin Abdulrahman al-Thani, speaking to reporters in Rome, said Doha remained ready to sit down and discuss the grievances raised by its Arab neighbors.
The comments came ahead of a deadline set by Saudi Arabia, the United Arab Emirates (UAE), Bahrain and Egypt for Doha to accept 13 demands. Officials say they are aimed at ending a rift that erupted last month over accusations that Qatar supports terrorism, charges it denies.
"This list of demands is to be rejected, not to be accepted. We are willing to engage in dialogue but under proper conditions," he said, Reuters reported.
The demands included severing ties with terrorist groups, closing down Al Jazeera satellite channel, downgrading ties with Iran and closing a Turkish air base in Qatar.
Arab states have said the demands are not negotiable and warned that further unspecified measures will follow if Qatar does not comply.
Sheikh Mohammed said Qatar would not close down the Turkish base in his country or shut Al Jazeera as demanded by the Arab countries.
He spoke after arriving in Rome from the United States. Washington is helping Kuwait, which has retained ties with Qatar, to mediate in the dispute.
Earlier on Saturday, the Kremlin said Russian President Vladimir Putin had separate telephone discussions with the leaders of Qatar and Bahrain about the rift and stressed the need for a diplomatic solution.