The state government will pass laws setting a new "minimum" length of time religious classes have to run in schools - to please upper house crossbencher Fred Nile.

Education Minister Adrian Piccoli announced the changes yesterday but rejected Mr Nile's plan to have ethics classes banned, forcing students to learn scripture.

The votes of Mr Nile and his Christian Democrat colleague Paul Green, and that of two Shooters MPs, will be critical in passing laws through the upper house in coming months.

The government will need the support of all four to get electricity privatisation and controversial police death and disability reforms passed.

Mr Piccoli said that, under current rules, there was a "maximum" time available for special religious education, but there would now also be a minimum - of 30 minutes a week in primary schools and one period in secondary schools.

"As school days have become busier, the provision of a maximum period of time has led to other activities encroaching on the delivery of special religious education," Mr Piccoli said.

"This regularly disrupts the thousands of volunteers that deliver the classes.

"The same minimum of 30 minutes meaningful teaching time per week will also apply to ethics classes.

"Ethics classes will remain in government schools because the government believes there ought to be an alternative provided for students who are not taking scripture."

Mr Piccoli recognised the efforts made by Mr Nile in supporting religion in schools.

sraising these issues regarding Special Religious Education".

Yesterday a Bill introduced by the Rev Nile to repeal ethics classes was allowed to be introduced into the upper house by the government.

Rather than oppose it, they referred it to a parliamentary committee for consideration, in another apparent sop to Mr Nile.

"The O'Farrell Government today confirmed it is [still] considering repealing ethics classes in NSW public schools," Opposition Leader John Robertson claimed.

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Originally published as Setting religious minimum for Fred