Johannesburg - Newly appointed Springbok captain Siya Kolisi is optimistic that 400m world champion Wayde van Niekerk will fill the void left by eight-time Olympic gold medallist Usain Bolt.

Speaking at the launch of Van Niekerk’s life documentary in Johannesburg this week, Kolisi said he was positive his friend would step up and be counted.

“I don’t think, I know he can step into his (Bolt’s) shoes because I know he is driven,” the Stormers player said.

The Zwide-born Kolisi said he knew Van Niekerk would not stop until he achieved what he wanted.

“He has a great support group around him and sticks with people who have been around him for a long time. He is determined and he wants to win.”

The 26-year-old said he was looking forward to what the International Association of Athletics Federations 400m champion was going to do.

“I have all the faith in him. I have faith in the man above, who gives him the power to do what he is doing. I am looking forward to seeing him do what people think can’t be achieved. I encourage him to keep going. He is a role model to me, my family and children, and to a lot of South Africans.”

Kolisi said he was confident Van Niekerk would continue to dominate the track for a long time because he worked hard and was committed to his dream.

“We chat daily. We share Bible verses. He really inspires me to be better,” Kolisi said.

Van Niekerk wrote his name in the history books when he broke Michael Johnson's 17-year record at the 2016 Rio Olympics. He ran 43.03 seconds in the 400m event.

Van Niekerk said: “I am prepared to build my own legacy. I want the next generation of reporters to ask other athletes how they feel following in the footsteps of Wayde van Niekerk.”