Floyd Mayweather says his next opponent will be decided within a week. But one thing's for sure: it's not Manny Pacquiao.

Mayweather, who arrived in South Africa on Wednesday, named Britain's Amir Khan and Argentina's Marcos Maidana as contenders for his next bout in Las Vegas on May 3 but said: "We don't know. We will know within the next seven days.'"

The undefeated Mayweather, now 45-0 after dominating Canelo Alvarez for a unanimous decision in September, also passed off eight-division champion Pacquiao's renewed attempts at making their mega fight happen as "desperation" because of the Filipino's unpaid tax issues.

"Two losses and tax problems later, now he all of a sudden he says, 'You know what? I'd do anything to make the fight happen'," Mayweather said.

"I offered Manny Pacquiao the fight before. We didn't see eye to eye on terms. Years later we come back and I try to make the fight happen again. I offer him $40 million. He said he wanted 50-50. So it didn't make happen.

"All of a sudden, he loses to Timothy Bradley, he loses to Marquez ... he has tax problems now. So, two losses and tax problems later he is really desperate and saying, 'Floyd, can you help me solve my tax problems, get me out of debt?'"

There is no doubt Mayweather knows his audience.

Boxing's superstar arrived wearing a T-shirt with a bright yellow map of Africa on the front. Below it, his TMT logo - which stands for The Money Team - was in the colors of the South African flag.

Mayweather told South African fans he had arrived in the "motherland". He even said he might fight in South Africa one day.

Mayweather swooped into Johannesburg for the start of a four-city visit to the country on his first trip to the African continent.

He was hustled by security straight through a packed airport terminal and into a Rolls Royce. He sped off with no more than a few words, delivered on the run, to hundreds who had gathered to greet him.

It didn't seem to disappoint any of them.

Later, Mayweather was more generous with his time, speaking to reporters for about an hour about his future fight plans and this trip. Well, part of the audience was reporters. Many fans had also somehow infiltrated the news conference, beefy security and all, meaning there were fewer questions and more statements of Mayweather's general greatness.

James Dalton, a former South African rugby international, stood up and thanked "Mr Mayweather" for making the trip and honoring South Africa.

Rugby players are a big deal in South Africa, but Mayweather apparently is bigger.

No surprise that Mayweather earned a guaranteed $41.5 million in his last bout, a dominating majority decision over Alvarez that was the richest fight in history and made around $150 million on TV sales alone.

And with those kinds of figures, the 36-year-old five-division world champion is in no rush to give in to Pacquiao's pleas for a fight, he said.

"As far as my last fight with ... I can't even remember the guy's name. Canelo! That's it. They are all the same to me," Mayweather said.

"So, as far as my fight with Canelo, they said my record could never be broken without the Pacquiao fight, but you have seen what we did - that fight did crazy numbers."