TOKYO (Reuters) -Japanese firms have agreed to raise pay by 5.25% this year, the biggest rise under comparable data since 2013, the country's largest union group Rengo confirmed on Friday.

The results of the closely-watched wage negotiations are announced in several stages, in which the blue-chip firms are first to wrap up their talks in mid-March.

The second announcement on the outcome of annual labour talks on Friday was little changed from a preliminary figure of 5.28% a week ago, indicating the strength of wage growth. The agreed hike of 5.25% corresponds to an average rise of 16,379 yen a month.

As a number of companies, small firms in particular, reach agreements on pay towards April-June, the average growth of pay hikes tend to become smaller than the initial round as more announcement becomes available.

Further results are scheduled to be released on April 4 and April 18, when more small firms come up with their results.

"We will examine how broad the trend of wage hikes is spreading at a meeting on April 4," Akira Nidaira, a senior Rengo official told a news conference.

Prime Minister Fumio Kishida has said the government is counting on wage hikes to trickle down to smaller and medium-sized firms, which account for 99.7% of all enterprises and about 70% of Japan's workforce, but many lack the pricing power to pass higher costs to customers.