One of Nelson Mandela's cherished dreams of building a southern African paediatric hospital is struggling to take off as the anti-apartheid hero is increasingly too frail to personally raise funds.

It was about a decade ago when the former president conceived the idea of a specialist children's referral and teaching hospital.

He had spent days visiting a child being treated in an intensive care unit of a Johannesburg private hospital for 80 percent burns, witnessing the agony that both the parents and the five-year-old boy went through.

The boy later died.

A discussion about the lack of children's critical care wards ensued and the idea of a dedicated children's hospital was born: a 200-bed paediatric facility for the southern African region based in Johannesburg.

Africa has only four children's hospitals -- two in Egypt, one in Kenya and one in SA -- a Red Cross hospital in Cape Town -- all built several decades ago.

Construction of the one billion rand ($120 million, 99 million euro) hospital is planned to start in November and the first patient should be admitted on July 18, 2014 -- Mandela's 96th birthday.

But amassing the funds has been "tough, it's very tough," said the Nelson Mandela Children's Fund executive director Sibongile Mkhabela.

"Depending on what we get we are ready to break ground in November."

After some seven years of research, about a fifth of the targeted funds have been secured, and for construction to kick off, at least half of the project funds should be available.

"We have collected about 200 million rands but we can only break ground when we have secured at least 500 million, that gives us confidence to break ground," she said.

A new "very powerful campaign" of two songs by South African artists to run on public radio stations was launched on Monday. "Using that public platform we believe we will be able to make the 500 million rands before November in order for us to break ground."

While raising funds was easier during the research phase of the project, when Mandela was still active, lately it has been an uphill struggle.

Going around with a begging bowl "could not be at worst of times, when the economy is melting down. When we started the research (in 2005) it was fine ... but now it's very hard for people to part with hard-earned cash in this environment," Mkhabela said.

But the frailty of Mandela, who turns 94 on Wednesday, has not helped the situation.

Had he still been active, she said they would "be done by now. He is an amazing fundraiser. He would have just made a few calls. We would be done," she said.

Funds have been sourced locally so far, but now the plans are to cast the net wider and target the international community.

"We want to go international. The work that is being done now is to rally around the local people to say we are the major anchors to this project, but we cannot do it alone," said the hospital project leader Joe Seoloane. "There's goodwill out there."

The Nelson Mandela Children's hospital, which will have lodging facilities for accompanying parents, is seen as the first to be proposed and built by "liberated Africans", Mkhabela said.

The "hope (is) that as we start this one it will be one of the first for the continent, but that there will be other Nelson Mandela Children's Hospitals throughout the continent, even beyond," she said.

"It's really a model, this is our first."

The hospital will be built on a 34,000 square metre (370,000 square foot) plot of land on the grounds of the Witwatersrand University in Johannesburg. It will also offer tele-medicine facilities for doctors in outlying areas as well as in southern Africa.