Maiava made 22 appearances for Hull this year - all from the bench

The 31-year-old former Cronulla forward has been released from the final year of his two-year contract.

It followed two disciplinary procedures resulting from "off-the-field" incidents in the last five months.

Chief executive James Rule said the club had been "thorough and careful" to ensure they had all the facts.

"We have done this, but I don't think it would be fair to comment on the specific incidents," he told the Hull Daily Mail.

"After an internal investigation and disciplinary process, it was decided to terminate his contract with immediate effect. But, yes it was a difficult decision."

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Maiava, who recently helped Samoa clinch the 10th and last place in the 2008 World Cup, made 22 appearances for Hull this year - all of them off the bench.

His replacement will be 30-year-old Cusack, who has been released from the final year of his contract with the Rabbitohs and has agreed a two-year deal with Hull.

Rabbitohs director of football Shane Richardson, a former Hull chief executive, said his club was happy for Cusack to pursue his new opportunity.

"This is reflective of the new culture we are building at the Rabbitohs, working with our players to achieve what is best for them and the club," said Richardson.