Renault, who are halfway through a long-term improvement project, and had hoped to close the gap to F1's big three this season.
However the French manufacturer finds themselves fifth in the standings, trailing behind Ferrari, Mercedes and fellow engine customers Red Bull and McLaren by 30 and 5 points respectively.
"I would say we are disappointed we are not further up," said technical director Bob Bell.
"We had hoped to take a bit more lap time out of the top three teams over the winter and we haven't.
"If anything they might have moved further ahead, so we are a little bit disappointed about that."
Bell praised fellow teams for making the midfield of the sport competitive adding:
"I think we are reasonably pleased with how we have positioned ourselves to McLaren, which we were very worried about when they came on board with the engine but clearly Toro Rosso and Haas have done a great job over the winter and are making life very difficult for us.
"It's going to be nip and tuck with them all season and McLaren are going to develop.
"McLaren are very good at developing to recover any losses from the start. It's going to be really closely fought. We had hoped to be a little bit further ahead at the start but this isn't an exact science and we know we can do a good development job in season."