The US state of Maine may break its agreement with Apple to buy thousands of iBooks.

Two state representatives have approached the Attorney General to find a way out of the state's multi-million dollar contract with Apple to purchase thousands of iBooks.

Maine governor Angus King is being pressured to scale the lucrative deal – worth $25 million – back to $15 million.

A pilot program using 2,000 computers was initiated after the legislation to buy iBooks for seventh and eighth graders was passed last year.

Plans to ship a further 16,000 this summer now hang in the balance.