He had called the office on Monday morning and told his manager, Winifred Ruru, that he had a damaged calf muscle and the doctor had advised he immediately take time off work.
Ms Ruru told Mr Taiapa he needed to provide a doctor's certificate.
Another worker at the organisation said he had seen Mr Taiapa on the Monday leaving town with his family.
On the Wednesday, Ms Maynard was shown a photo taken at a waka tournament in Rotorua in which Mr Taiapa had a "large female sitting on his knee", the authority said.
Ms Maynard said she became suspicious Mr Taiapa had used sick leave to attend the week-long waka competition.
Mr Taiapa saw his doctor on Monday, April 4, and was given a certificate that excused him from work from March 28 until April 7.
Mr Taiapa said how he managed his health was his business, and he believed he had done nothing wrong in travelling to Rotorua.
He said the case by Turanga Ararau was "constructed" against him and he was considering appealing against the employment authority ruling.