Daniel Vettori is concerned about his IPL contract © Getty Images

The head of the New Zealand Cricket Players' Association has described the Indian Premier League (IPL) contracts reportedly signed by Daniel Vettori and Scott Styris as "the worst contracts I've seen in professional sport". Heath Mills, the association's manager, said Styris had signed the deal but he was unsure if Vettori had committed.

Mills said the IPL and New Zealand Cricket (NZC) had pressured the players to accept the lucrative three-year deals or the offers would be withdrawn. "We recommended they didn't sign the contract put in front of them and I'm not sure Daniel has signed," Mills told the Dominion Post.

"The contracts put in front of the players are the worst contract I've seen in professional sport. Players around the world have been signing it and they have no idea what they are signing away. It does not stipulate the rights they are giving away to Indian cricket. I'm concerned our guys signing it will put them in breach of their NZC contracts.

"I don't think it is a very good contract at all. It is a one and a half page document. Our contracts are 100 pages long and people are very aware of their obligations and restrictions."

The paper reported Vettori was unhappy with a clause in the memorandum of understanding that "the player is not allowed to play for any other team that may at any point in time qualify for the Champions League". "I know Daniel is concerned about the contract put in front of him and is trying to get some late changes to it," Mills said.

The IPL is a domestic Twenty20 competition in India that will feature international players from other nations. The Champions League is an extension of that concept, with leading Twenty20 sides from domestic competitions around the world invited to play each other.

Vettori's Northern Districts team could therefore qualify, leading to his worries about the contractual clause. However, Justin Vaughan, the chief executive of NZC, told the paper he did not share the concerns of Mills and Vettori.