Neither Button nor Hamilton have started higher than fourth this season
McLaren are confident they can get a car on the front row of the grid for the first time this season at this weekend's Spanish Grand Prix.
Chief engineer Tim Goss said "significant upgrades" to the cars should give McLaren drivers Jenson Button and Lewis Hamilton a boost.
"I'd like to think we can put a car on the front row," Goss told BBC Sport.
"We've a new front and rear wing, both are reasonably major changes compared to the last version."
Although McLaren top the constructors' championship with 109 points and lead the drivers' championship through Button, they have been slower in qualifying than Ferrari and Red Bull.
So far this season their best qualifying position has been fourth by Button in Australia and Hamilton in Bahrain.
If it's a dry race, then realistically I think it's going to be harder for us to be up at the front
However, Mercedes GP driver Nico Rosberg has also out-qualified both McLarens in two of this season's four races.
And with the Barcelona track notoriously difficult for overtaking Hamilton is aware qualifying will be crucial on Saturday.
"As we did in China, we'll be putting additional emphasis on qualifying," said Hamilton.
"It will be more important than ever in Barcelona as traditionally it's always been a track where overtaking is very difficult.
"Given that most cars will only be stopping once, we have less scope for passing, so a good grid position will be vital."
Goss is yet to see Hamilton or Button start a race higher than fourth place this season, something the Woking-based team are eager to rectify.
"How we do in Barcelona depends on the changes we made to the car," said Goss.
"We've made a decent step but expect other teams will have too - obviously Ferrari have their own drag-reducing rear wing now too.
"I think it is very difficult to make any predictions about Barcelona."
World champion Button has won two races for McLaren this season, coming from fourth on the grid in Australia and fifth on the grid in China to take the chequered flag.
Meanwhile, 2008 world champion Hamilton is yet to win a race after starting in fourth position in Bahrain, 11th in Australia, 20th in Malaysia and sixth in China.
"At Malaysia we brought a significant change and we were really expecting to be competitive in qualifying," Goss explained.
"But due to the mistakes we made with the weather we never really got to demonstrate it.
"At China barring the slip-up Lewis had in qualifying we've proved we've closed the gap.
"We were probably two to three tenths of a second off Red Bull in China."
And Hamilton is confident McLaren will continue to improve the car throughout the year.
"Of course, we've proved in the past we've been both extremely capable and prolific at adding performance to the car across the course of the season, so I'm hopeful we're heading into Barcelona in good shape," said Hamilton.
Formula 1 should be an ambassador to new technology, and I have hope that sponsors will then come back
"But if it's a dry race, then realistically I think it's going to be harder for us to be up at the front."
As McLaren seek to shave time off their qualifying times there has also been a suggestion Formula 1's Kers power-boost systems could make a comeback next season.
Ferrari and Renault have offered to supply the systems - scrapped by teams last year for cost reasons - at lower prices and with higher energy levels.
And the president of the sport's governing body (FIA), Jean Todt, said he was "very serious" about Kers making a comeback when costs are cut in 2011.
"We need to pursue new technologies because F1 should be an ambassador to new technology, and I have hope that sponsors will then come back," said Todt.
However, while McLaren would back the return, Goss insisted time is running out to implement the system for next season.
"We fully support what the Formula 1 Teams' Association (Fota) and the FIA are trying to do in terms of Kers," said Goss.
"Clearly to introduce it for next season, it's starting to get a little bit late in the day. But there are lots of people working on this.
"We understand the need for Kers for the association with road car technology, and we think it's the right thing to bring it back.
"Really we'll just go along with whatever Fota and the FIA decide."
Many current "hybrid" road cars use the Kers system which works by storing energy that would otherwise be wasted as heat during braking and re-applying it to either boost power or cut fuel consumption during acceleration.