Mani criticised the world governing body's decision to reduce the 2019 World Cup to 10 teams and said that many of the game's 10 Full Member nations faced serious challenges.
"A year has passed since the changes at the ICC," Mani said at the launch of the new Wisden Cricketers' Almanack at Lord's, in reference to last year's takeover at the ICC by the boards of England, India and Australia.
"I am more concerned about the health of the game today than I have ever been. When I look around, five of the 10 Full countries are in desperate need of help. They are faced with two main challenges: one, not enough money; two, not enough quality cricket."
"It is desperately sad to see that some of the West Indian players prefer to play in the IPL (Indian Premier League) and other T20 leagues around the world rather than for West Indies," he said.
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"This is simply because of money. This problem must be addressed. It is the responsibility of the ICC to ensure that the priority for players should be to play for their country before anything else.
"They will require $30 million (27.8 million euros) to $50 million more over the next eight years than what they will receive from the ICC and from the sale of their commercial rights."
Mani expressed concerns over the futures of the Associate nations, who may not feature at the next World Cup if the two qualifying berths made available to teams outside the world's top eight are taken by Bangladesh and Zimbabwe.
He said the Associates needed more funding from the ICC and more opportunities to play against Full Member nations, adding that the World Cup "should be inclusive not exclusive".
"A lot of lip service is paid to preserving and protecting Test cricket. The reality is somewhat different. Sri Lanka toured England last year and played just two Test matches. India was given five Tests, purely because that would mean more money for the host," Mani said.