Gov. Neil Abercrombie has signed into law a measure that gradually phases in requirements for more class time in public schools.

The measure rolls back a law passed last year that would have mandated increases in instructional time at public schools starting next school year.

Instead, the bill Abercrombie signed into law Thursday delays for three years the new requirements for high schools and middle schools.

Half of elementary schools elementary schools will have to teach a minimum number of hours starting next school year, with the other half catching up the following year.

Legislators said an immediate jump in instructional time would have created difficulties in adjusting school schedules, and the state can’t afford to pay teachers additional money.