Villas-Boas insists no deadline had been set for an agreement to be reached with Cahill, who would become his first January signing for a reported fee of £7million, but the 26-year-old's move to Stamford Bridge is believed to be close.
Villas-Boas said on Thursday afternoon: "Still ongoing negotiations, not that we don't want it solved as soon as possible.
"We're making good, solid progress."
Villas-Boas refused to criticise Cahill or his representatives for the delay, amid reports they were holding out for wages of £100,000 per week, £30,000 more than Chelsea were said to have offered.
"It's part of negotiation," Villas-Boas said.
"I'm sure all parties are protecting their interests and we'll reach an agreement.
"Let's hope to conclude it this week."
Chelsea cannot afford the impasse to continue for another fortnight of the January transfer window.
But Villas-Boas is confident of being able to move quickly for other targets should the Cahill deal collapse.
"We kept a couple of other options available and hopefully we can act quickly if that's the case," he said.
"But I'm pretty confident it will happen."
If there is no movement before the weekend, Cahill will be in contention for Bolton's trip to Manchester United.
Wanderers boss Owen Coyle said on Thursday morning: "Dialogue continues between Gary's agent and Chelsea.
"We accept it has probably been long-drawn. It is over two weeks ago that we agreed a fee.
"But sometimes that is the nature of football business. It can take that period of time.
"Gary is a Bolton player and, until I hear something different in terms of negotiations being concluded between both parties, he will be in line to play against Manchester United."
It has been suggested rival suitors have made their interest in Cahill known.
However, this was news to Coyle, who insisted Chelsea remained the only current option for the player.
"If other clubs are linked with him, it is just speculation," Coyle said.
"We have agreed a fee with Chelsea. I have had no dialogue with any other club.
"We recognise it is the silly season but I don't deal in rumour. I only deal in fact.
"The fact is we have agreed a fee with Chelsea. We have not spoken to anyone else. That is where we are."
While Cahill looks set to be heading into Stamford Bridge, Alex could soon be heading out, with Villas-Boas confirming that a bid has been received for the wantaway defender
Villas-Boas said: "From what I know from my chief executive, there has been an approach from a Premier League club.
"We have respected Alex's transfer request so the market's open for him.
"We're just trying to reach the level of proposal we think is good for the player. Nothing has happened up to now, but we'll listen to all offers.
"We'll present anything to the player.
"He has to make a decision. He has generated interest from a lot of clubs."
The bid is thought to have been lodged by QPR, with Mark Hughes all but confirming his intention to sign Alex at his official unveiling on Wednesday.
"There is interest in top-quality players and the player you mention is very much in that level," Hughes said.
Alex, who was banished from Chelsea's first-team squad along with Nicolas Anelka after both submitted transfer requests, has previously been linked with Juventus and Paris St Germain.
He also recently admitted he would consider a return to Santos in his native Brazil.