The Italian squad has endured its worst start to a Formula 1 season since 2009, when it failed to score a single point in the first three races of the campaign.
Its lack of performance compared to pacesetter Red Bull prompted Sainz to suggest at the Australian Grand Prix that it was in need of a direction change.
"At the moment the Red Bull is superior everywhere," said Sainz. "It's superior in quali, in races, in straightline speed.
"They are superior in medium/low-speed corners, they are superior with tyre management, superior over the kerbs and bumps. It just shows that we clearly need to change something.
"We need to go and check something very different from where we are now. I think the extremely good performance at the start of last season made us, I think, keep pushing with this concept, with this project of car.
"But I think we realise now that Red Bull has a clear advantage everywhere and that we need to start looking to our right and to our left."
But while there have been rumours in recent weeks that Ferrari was ready to embark on radical changes, including a shift of sidepod concept, such a move has been dismissed by team principal Fred Vasseur.
Instead, Vasseur says the team's plan is for three stages of upgrades over the next few months that he hopes will be enough to make a difference.
Asked by Autosport if a change of concept was coming, Vasseur said: "No, I don't think so.
"We have a flow of updates that will come, not for Baku, because we have the aero package for the level of downforce, and with the sprint race it is not the easiest one, but for Miami, Imola, not Monaco, and Barcelona. At each race, we'll have an update on the car.
"We are sticking to the plan. We have made some adjustments in terms of balance and behaviour, and it was much better in Melbourne, and we'll continue in this direction.
"It's not a B-car if that is what you want to say. We won't come with something completely different. We will continue to update this one and we'll try to update massively."
Vasseur explained that the restrictions teams faced with both F1's cost cap and wind tunnel hours meant that changing concepts at this stage of the season was too tough a task.
"To do a new project during the season, to start from scratch, to do a new car with the cost cap, but also considering the restriction of the wind tunnel time, I don't want to say that it's impossible, but it's very difficult.
"Also, on our side, we have the feeling, and I hope that we are right, that we are going in the right direction, that we have still tons of room for improvement on the car.
"It means that as long as we are still able to develop the car to get [downforce] points, and the aero to get a better balance, to get a better stability and so [on], I think it makes sense to push in this direction."
Ferrari's preferred response to its difficult start to 2023 is to speed up the introduction of planned upgrades, rather than do something different with its car and start from scratch.
Vasseur added: "You have always a plan of development before the season, and then you have to react due to the circumstances, due to the competitiveness of the car, and due to the behaviour of the car. We took action very quickly.
"We brought some good updates in Melbourne, and we will continue. What we can do is to push to try to speed up this process, perhaps to take a direction a bit different in terms of balance and so on.
"But we can't change massively the plan after three races and say, 'okay, we have to go in another direction.'"
But while a big concept change has been ruled out for this season, Vasseur is open-minded about the team perhaps needing to take a different path with its 2024 car if things do not improve.
"The question is [really] about the cost cap: if you want to do a carry over or not," he said. "And which parts do you want to carry over between one season to the other one – like the big components of the gearbox or monocoque? It's a question that we'll have to manage with the cost cap.
"With the strategy of development, I think we have good updates. And we'll see later on into the season if we want to do a continuous improvement of this one, and we have room for improvement, or if we have to change more massively the direction. We will see that much later."
Additional reporting by Alex Kalinauckas
