Hamilton's answer, on whether he remains with McLaren or opts to move to Mercedes, could potentially come as early as Friday, although it is understood the situation is not 100 per cent finalised.
The likelihood is Hamilton will continue his partnership with McLaren that now stretches back 14 years after he was initially signed up as a 13-year-old.
Press Association Sport was told by a source close to McLaren after the Singapore Grand Prix on Sunday that a contract to stay loyal to the Woking-based marque was "85-90 per cent" resolved.
Given the current economic climate, McLaren's initial offer saw them slash the 27-year-old's yearly salary by a third from £10million to around £6.75m and on a par with team-mate Jenson Button, resulting in the need to look elsewhere.
With management company, XIX Entertainment run by impresario Simon Fuller, known to have entered into negotiations with Mercedes, the German manufacturing giant then put in a sizeable bid.
It is understood Mercedes also offered Hamilton greater freedom with regard to his image rights and less impact on his personal time from corporate sponsorship appearances.
With McLaren's hand forced, they are believed to have increased their annual salary offer by a further £2m, and more in line with Mercedes.
Further negotiations have taken place behind the scenes these past few days since the race at the Marina Bay Street Circuit where team principal Martin Whitmarsh and Hamilton both appeared more relaxed.
It was in stark contrast to the tense atmosphere that pervaded the paddock at Spa-Francorchamps for the Belgian Grand Prix as Hamilton landed in hot water with the team for tweeting telemetry data from qualifying.
A few days later, when former team boss and current BBC television pundit Eddie Jordan remarked a deal with Mercedes was done and an announcement imminent, it sparked a feeding frenzy at Monza ahead of the race in Italy, with Hamilton bombarded with questions.
Hamilton, however, kept his cool on the track to win from pole and thrust himself back in the title hunt, following which McLaren began their concerted push to retain the 2008 world champion.
Another pole followed in Singapore, yet despite what Hamilton described as a "heart-breaking" gearbox failure when comfortably leading, he was positive and upbeat when he spoke after the race.
It was similar with Whitmarsh who claimed McLaren and Hamilton "are a good team together", with the latter dealing with his disappointment "as a world champion".
Whitmarsh refused to speculate on whether a deal would be done before Japan, which starts next Friday in Suzuka, but it now appears certain that will be the case, with McLaren seemingly beating Mercedes to Hamilton's signature.
Mercedes team principal Ross Brawn today indicated talks were ongoing with Michael Schumacher, whose three-year contract expires at the end of the current campaign.
"It's still under discussion, I'm afraid," said Brawn on BBC Radio 5 Live.
"I can't comment very much on that, but Michael's been a huge asset to the team, he's really taken us forward.
"I do think Michael contributes an awful lot, so I think the decision for Michael to stay or not continue is a difficult one.
"Obviously he's very involved in that decision, and discussions are ongoing at the moment"
Asked whether Hamilton could be joining Mercedes, Brawn naturally ducked the issue, adding: "I think any ambitious team looks at the top drivers and we're an ambitious team.
"But I think there's an awful lot of speculation. We will have some things to say in the next few weeks, next few months, and then all will become clear."
When contacted, McLaren issued a "no comment".