The government wrote again to Achakzai, offering tea with the prime minister, while he insists on a neutral venue and a serious invitation after the KP emergency.
The government invited Mahmood Khan Achakzai, the opposition leader in the National Assembly, for talks with PM Shehbaz Sharif on constitutional issues.
Rana Sanaullah, the PM's adviser on political affairs, said the government had written to Achakzai again, offering tea with the prime minister.
Achakzai wants a neutral venue or a serious invitation, and said earlier rounds of talks had produced little beyond ridicule.
The dispute follows the imposition of emergency and governor's rule in Khyber Pakhtunkhwa on October 11.