The 24-year-old, having run personal bests in the 100m (9.94sec) and 200m (19.84sec) last month, set a new world best time of 30.81sec in the rarely-run 300m in Ostrava last week, beating a long-time record held by Michael Johnson.
But now van Niekerk is ready to turn his attentions back to the distance in which he is also the reigning world and Olympic champion, having run the world-record time of 43.03sec in Rio de Janeiro last August.
"I definitely know that I'm in good shape in every single distance below 400m, except the 400," the South African told a press conference on Wednesday.
"It's about continuing this really good form that I've been building and improving both my 200 and 400m times.
"I'm glad that I had the opportunity to improve both my 100 and 200m times, but I guess now it's back to business and time to try and get some good form in the 400m for the world championships and put up a good show in the world champs in London this year."
Eight-time Olympic champion Usain Bolt has hailed van Niekerk as his successor as leader of the sprinting world, with the Jamaican legend due to retire after the world championships in London in August.
Van Niekerk is the only man in history to have run under 10 seconds for the 100m, 20sec for the 200m, and 44sec for the 400m.
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