Mohammed al-Arisha says spy chief Salem al-Hassi submitted his resignation to the parliament today.
The al-Wasat news portal says al-Hassi resigned because he was frustrated with parliament's insisting on appointing a new prime minister in a contested vote.
Al-Hassi could not be reached to confirm the report.
The appointment of Premier Ahmed Maiteg by parliament last month added to Libya's crisis after incumbent premier, Abdullah Al-Thinni, refused to hand over his post, insisting the judiciary should resolve the issue.