Pacquaio is regarded the world's best pound-for-pound fighter
Five-weight world champion Manny Pacquiao and unbeaten American Floyd Mayweather are set to meet on 13 March, according to the Filipino's promoter.
Michael Koncz, who is in charge of Pacquaio's promotional company, says the 30-year-old has agreed to a March proposal from promoter Bob Arum.
"We all believe that it will be done," Koncz told GMA television.
If the 'super fight' goes ahead, it will match the two men regarded as the world's best pound-for-pound fighters.
"Arum presented what he thought was the best proposal he can bring during a two-hour breakfast meeting with Pacquiao in Manila," added Koncz.
"Manny has some additional requirements, requests, which Arum didn't think was a problem.
"The requests of Manny were so realistic that Arum doesn't feel it's a problem and it's pretty much a done deal."
Pacquiao's trainer Freddie Roach, who is preparing Britain's Amir Khan for his first WBA light-welterweight defence on Saturday, also confirmed the date.
"I talked to Arum and Manny is happy with that date and I can't wait to get started," Roach told Sky Sports.
"It will be the biggest fight of all time and Amir Khan will help us get ready for the fight with his speed a lot like Mayweather's."
But Roach confirmed that the fight was not a done deal but was closer to being finalised.
"There will always be negotiation and there are issues such as weight, but they can always be solved," added Roach.
"It is would be a tough fight and we will need to set some traps and work on some strategies. But it is a fight Manny wants, he is very confident he can beat Floyd."
Pacquiao last fought in November beating Miguel Cotto in Las Vegas. The Filipino stopped his Puerto Rican opponent in the 12th round of their WBO welterweight clash at the MGM Grand with a stunning display.
Mayweather, 32, returned to the ring for the first time in 21 months with a unanimous points victory over Juan Manuel Marquez in Las Vegas with a classy performance.
Pacquiao is running for a congressional seat in the May 2010 elections and official campaigning will not start before April, making the March date convenient for the Filipino.
No venue has been decided for the mega fight but representatives of the Superdome in New Orleans and the new Dallas Cowboys' stadium have expressed interest in hosting the fight, as has the MGM Grand hotel-casino in Las Vegas, where the pair have fought their biggest fights.
There is also a proposal for a 30,000-seater temporary stadium on the Las Vegas Strip across from the Wynn resort.