MANILA (AFP) - Philippine boxing hero Manny Pacquiao hinted on Monday his fight against American Floyd Mayweather could be his last, saying he would head into the May bout with retirement on his mind.

"It is coming close. We will announce it," the 36-year-old told local television network ABS-CBN with a smile when asked about retirement.

After years of failed negotiations, Pacquiao and Mayweather hammered out a deal to face each other in Las Vegas on May 2 that will finally give fans the chance to see the best pound-for-pound fighters of their generation face off.

Pacquiao said he agreed to take a smaller cut of the purse just so the fight could push through.

"If we only thought about our pride, there would not be a fight. If we had equal pay, the fight would not have pushed through so for the fight to push through, I agreed to it," he added.

US media has reported that Mayweather, who turns 38 this week, will receive 60 per cent of the purse.

Pacquiao has held world championship belts in eight divisions, and will go into the fight with a record of 57-5, with two draws and 38 knockouts.

Mayweather has a 47-0 record with 26 knockouts. He is homing in on the iconic 49-0 record of 1950s legend Rocky Marciano, who retired as an undefeated heavyweight champion.

Pacquiao reiterated that he actually enjoyed being rated below Mayweather by oddsmakers in Las Vegas.

"I like being the underdog. I am more motivated," he said.