Ms Yingluck had not assigned representatives to send her request to council leader Gen Prayuth Chan-ocha through the NCPO secretariat as some media reports had claimed, said Lt Gen Kampanat Ruddit, director of the NCPO's Centre for Reconciliation and Reform.
The former premier's scheduled return date of Aug 10 so far remained unchanged, said Lt Gen Kampanat.
A source close to Ms Yingluck and her lawyer, Norawit Lalaeng, said they had not been informed about any postponement and said Ms Yingluck had not assigned anyone to extend her return date.
Surapong Tovichakchaikul, a former deputy prime minister, said Ms Yingluck currently was in a country "not far" from Thailand. It was expected she would arrive home in the early hours of Monday, he added.
Ms Yingluck travelled to Paris last month and took part in 65th birthday celebrations on July 26 for her brother Thaksin. There has been considerable speculation that she might choose to remain abroad rather than come home, where she is facing charges of dereliction of duty in connection with her government's failed rice-pledging programme.