Astana rider Fabio Aru, who finished third in last year’s Giro d’Italia, says he will sue Greg Henderson after the New Zealander appeared to publicly accuse him of feigning illness to cover up issues with his biological passport.

Aru, aged 24 and among the leading contenders for the Italian Grand Tour next month, failed to start the Giro del Trentino earlier this week due to a stomach virus.

His team’s sports director Paolo Slongo saying the Sardinian rider had been extremely ill last weekend after returning home from a training camp on Tenerife.

On Thursday evening, Lotto-Soudal rider Henderson tweeted: “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!”

Shortly afterwards, he added: “I am so sick of it. It becomes common knowledge within days. Why try cheat.”

Henderson’s tweets were posted the same evening that the UCI confirmed that its Licence Commission had rejected its request to revoke the WorldTour licence of Aru’s Astana team.

The tweets have now been deleted, and yesterday morning Henderson issued an apology to Aru on the social network, saying: “When you are sick. You are sick. Jumping to conclusions helps nobody. My mistake @FabioAru1. I should shut my mouth. Sincere apologies.”

But in a statement published on his website yesterday, Aru said: “With regard to the statements published on 23 April 2015 on Greg Henderson’s Twitter profile, Fabio Aru has instructed the lawyer Mr Napoleone in order to take legal action against the New Zealander cyclist to protect his image and honour.”