Jonathan Norbury, 35, from Swansea, denies having sex with three girls under the age of 16.
He was cleared in court in January 2015 of alleged offences with two of the girls, who he did not teach.
The Education Workforce Council (EWC) hearing to decide if the allegations are true was adjourned on Monday.
The panel failed to reach a decision within the allocated period of time.
The hearing in Cardiff was previously told Mr Norbury was sacked from Casllwchwr Primary School, in Loughor, for gross misconduct after the trial in 2015.
Yet he was given an Â£8,000 payout and a glowing reference from Swansea Council.
Mr Norbury accepts he had sexual relationships with the girls but he maintains none were below the legal age of 16 when he was with them.
If the EWC panel decides the allegations are true, he faces a range of sanctions, including being banned from teaching.
A deputy head teacher sacked for allegedly having sex with teenage girls will have to wait to find out his fate.