South Korea's producer prices rose to a five-year high in September as the unprecedented heat wave in the summer undermined crop production and pushed up prices of agricultural goods.

According to data by the Bank of Korea on Tuesday, the producer price index, a barometer of future consumer inflation, reached 105-point-78 in September, up point-three percent from a month earlier.

That's the largest since August 2013, when it reached 105-point-81. 

On a year-on-year basis, the index rose two-point-seven percent to extend its positive streak to 23 straight months from November 2016.

Prices of agricultural and fishery products gained one-point-five percent on-month to reach a record 136-point-57 last month, the highest since the BOK started compiling related data. 

Prices of industrial goods rose point-three percent on-month, while service sector prices gained point-one percent.