Pretoria - Former Springbok Joost van der Westhuizen says his condition has neither improved nor deteriorated after undergoing experimental stem cell treatment last month for a fatal motor neuron disease.

Van der Westhuizen, 40, said in an interview on Talk Radio 702 on Tuesday that he was enjoying some "alone time" in Dubai, where he was working, but he appreciated the support he had received in South Africa.

"There are a lot of people behind me," Van der Westhuizen said.

"I have a great support system, including my parents and my kids.

"I need to keep positive because stress is not good for me."

The former scrumhalf, who played a pivotal role in the host nation's victory in the 1995 Rugby World Cup, said the Springboks had "surprised everyone" with their dominant form in Pool D at the global showpiece in New Zealand.

The Boks, who face Samoa in Auckland on Friday, have won their opening three matches of the tournament.

Van der Westhuizen also congratulated wing Bryan Habana who scored against Namibia in their third match of the competition, dotting down for the 39th time to break Van der Westhuizen's Springbok try-scoring record.

Habana had paid tribute to Van der Westhuizen after the match.

"Records are there to be broken and I'm glad he did it," Van der Westhuizen said.

"Bryan has given a lot to SA rugby and it's good to see these young guys coming through and playing their part."