TOKYO (Reuters) -Top Japanese companies agreed to wage increases of an average 5.58% at annual labour talks that wrapped up in March, the Keidanren business lobby's preliminary data showed on Monday, representing the heftiest pay hike in 33 years.

The average wage increase at the "shunto" spring wage talks this year exceeded last year's finalised 3.99% increase and came close to the 5.6% recorded in 1991.

The rising wages reflect Japan's chronic labour shortages, as well as efforts to help employees tackle rising consumer prices.

The annual pay negotiations - called "shunto" or "spring labour offensive" - are one of the defining features of Japanese business, where relations between labour and management tend to be more collaborative than in some other countries.

The country's largest union group Rengo has said that Japanese firms had agreed to raise pay by 5.17% this year, the biggest rise under comparable data since 2013.

Keidanren's survey covers 244 large companies with 500 employees or more in 22 sectors. The preliminary data was derived from 89 companies in 16 sectors. Final data will be published in late July.