Cycling: Greg Henderson in the soup following Twitter outburst

Greg Henderson in action for his Lotto-Soudal team. Photo / Getty Images

Kiwi cyclist Greg Henderson has courted controversy with a Twitter outburst directed at a fellow pro tour rider on the European circuit.

Henderson, who rides for the Belgian Lotto-Soudal road racing team, made the comments about Italian professional Fabio Aru of the Astana team following Aru's withdrawal from the Giro del Trentino event.

The International Cycling Union recently investigated Astana in relation to anti-doping issues. The Associated Press reported this week that the outcome of the review was that Astana would retain its top-tier racing status but would be "subject to strict monitoring"

According to the roadcycling.co.nz website, Aru cited illness as his reason for withdrawing from the race. Henderson reportedly posted the following tweet about Aru, which has since been deleted:

"Sad to see @fabaro1 'sick'. Mate make sure next time u come back to our sport 'healthy'. Aka Clean! #biopassport! Or don't come back!"

Henderson, who won gold for New Zealand on the track at the 2002 Commonwealth Games, is also said to have posted another controversial tweet, which read:

"I am so sick of it. It becomes common knowledge within days. Why try cheat."

The Astana team reacted angrily to the outburst, with coach Paolo Slongo intimating Aru could take legal action over it.

Aru's agent Alex Carera also waded in, according to roadcycling.co.nz.

"A famous athlete like Greg Henderson who has 30,000 followers on Twitter can cause huge damage to a person like Fabio, his Astana team, and the sport," said Carera. "Our lawyers will look at what has happened and consider where to start legal action."

Henderson has since apologised for his comments by posting the following message on Twitter:

"When you are sick. You are sick. Jumping to conclusions helps nobody. My mistake @FabioAru1. I should shut my mouth. Sincere apologies."

When you are sick. You are sick. Jumping to conclusions helps nobody. My mistake @FabioAru1. I should shut my mouth. Sincere apologies.

— Greg Henderson OLY, BSc. (@Greghenderson1) April 24, 2015