Italian rider Fabio Aru's agent and lawyer have confirmed that they will begin legal action, along with the Astana team, against Greg Henderson for the accusations he made against the Astana team leader on Twitter.
The situation follows posts Henderson made on social media site Twitter last month. Henderson later deleted the tweets and posted an apology.
Late on the evening of April 23, just hours after the UCI Licence Commission confirmed that the Astana team could keep its WorldTour licence, Henderson took to Twitter, writing: "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!"
He followed that up by posting: "I am so sick of it. It becomes common knowledge within days. Why try cheat."
Henderson has close to 40,000 followers on Twitter.
He later apologised and removed the Tweets, writing "When you are sick. You are sick. Jumping to conclusions helps nobody. My mistake @FabioAru1. I should shut my mouth. Sincere apologies."
While Aru had previously said he planned to take Henderson to court, the New Zealander had hoped the incident had died away after he apologised.
However, Cyclingnews.com has reported that Aru's agent Alex Carera and lawyer Giuseppe Napoleone had struggled to get proceedings underway because Henderson is based in Spain but rides for Belgium team Lotto Soudal.
Legal action will be taken "to protect the good name and honour of Fabio Aru and the team [Astana] that he rides for," Cyclingnews.com said.
Henderson said on Tuesday that he still had not heard anything from Aru's representatives.
Both riders are currently involved in the first Grand Tour of the season, the Giro d'Italia.