Milan (Reuters) - A Milan civil court on Thursday rejected an appeal against the wording of a Dec. 4 national referendum on constitutional reform.

Valerio Onida, a former constitutional court judge, brought the case arguing that it was unacceptable that the ballot sheet lumps together multiple issues into one question requesting a single 'yes' or 'no' answer.

Opinion polls suggest Prime Minister Matteo Renzi may lose the ballot over his proposal to drastically reduce the role of the Senate and curb the powers of regional governments.

All but one of 33 opinion polls conducted over the last month have put the 'No' camp ahead

On Nov. 16, an administrative court in Rome will hear another appeal made by Onida against the referendum.

The same court has already thrown out a similar case brought by opposition parties, although Onida's case does have some technical differences.

(Reporting by Manuala D'Alessandro, writing by Gavin Jones, editing by Isla Binnie)