Both sides are openly discussing the details of a new deal for 2019 and beyond.
Hamilton is quoted by La Repubblica as saying: "We have not done anything official yet but the atmosphere between us is relaxed.
"I have a commitment to the team and they to me, so I hope to sign soon.
"If it's not soon, no problem, but it will happen sooner or later."
Quadruple world champion Hamilton is entering the new season as the favourite, but he agrees with his boss Toto Wolff that Red Bull is the dark horse.
"I think Red Bull potentially have the fastest car," he said at a sponsor event in Turin.
"I understand their upgrade for the first race is two to four tenths per lap."
The new season gets underway next weekend.