MADRID, Sept 5 (Reuters) - Just 9 percent of Spaniardsdefinitely plan to take part in a general strike against wageand pension cuts planned for Sept. 29, down from 15 percent in aJuly poll, a poll showed on Sunday.

The percentage who believe the strike is justified grew to58 percent of those polled by Metroscopia for El Pais newspaper,up from 51 percent in July. But those who said a strike is notappropriate grew by 15 percentage points to 56 percent.

Prime Minister Jose Luis Rodriguez Zapatero has approved 15billion euros ($20 billion) of spending cuts and carried out areform of labour laws making it easier to hire and fire as partof measures aimed at renewing faith in Spain's economy.

Spain's two biggest unions, traditional supporters of theunpopular ruling Socialist party, have called for a generalstrike in September against austerity measures, in coordinationwith other unions in Europe.

The opposition centre-right Popular Party increased its leadover the Socialist PSOE in approval ratings to 8.9 percentagepoints, the poll showed.