Gibbes said he would be requesting clarification on the issue with New Zealand Rugby's referee manager Bryce Lawrence.
"The question that needs to be answered is 'Is that within the spirit of the game?' If it is, then I think everyone should do it, but if it's not, well, there are higher people up the food chain than me to answer that."
However, Otago head coach Cory Brown denied there was any nefarious intent with his substitutions, and explained the situation with Renton and Parker's short stints on the park.
"Both of them picked up injuries so I had to get the guys that they replaced back on - Josh Renton injured his Achilles, and our medical team were a bit concerned he was going to rupture his Achilles so we took him off, and Hayden Parker rolled his ankle. So they were both legitimate substitutions.
"The guys who went off weren't injured - they were tactical, and then they came back on for the injured player," Brown explained to Radio Sport.
"That's part of the rules - you're able to replace guys who are injured, because if you didn't, it would be the walking wounded out there. Certainly no tactics involved in it."
Substitutions aside, Wellington eventually sealed the victory with a 75th minute Jackson Garden-Bachop penalty to extend their lead atop the Championship.
Elsewhere, Counties Manukau have moved out of the Premiership relegation zone with a 25-16 victory over Northland.
A late try to Stephen Donald saw Counties strike late to move into sixth, three points ahead of Waikato with two games remaining. Northland sit in fourth on the Championship ladder.