Eight-time Grand Slam champion Agassi teamed up with Djokovic ahead of the French Open, where the Serb is attempting to defend his title.
Agassi, who won Roland Garros in 1999, said he is not being paid to mentor Djokovic but simply wants to help him find his best form again.
"For me, I do this on my own time and my own dime," said Agassi.
"I don’t want money, I want to help him. And it helps the game. Him at his best is good for the game and it’s a way I can contribute."
Agassi initially committed to just a "few matches" with the former world number one, but the American told Eurosport he was open to working with Djokovic at Wimbledon.
"If he wants me there, yeah, I will come," said 1992 Wimbledon champion Agassi, speaking to Djokovic's former coach Boris Becker.
"It’s a lot of responsibility so whatever’s practical and achievable – 100 percent I will make the effort."
Becker gave up coaching Djokovic last December after three successful years together, while the 12-time major winner split with long-time coach Marian Vajda last month.
He then named Agassi after he lost to Alexander Zverev in the Rome Masters final a fortnight ago.
Djokovic reached the last 16 on Friday thanks to a 5-7, 6-3, 3-6, 6-1, 6-1 wn over Diego Schwartzman of Argentina.