Japan star Shinji Kagawa says he won't use the World Cup to impress Manchester United's new manager Louis van Gaal, despite being largely ignored by sacked David Moyes this season.

"I think everyone knows I want to do well at the World Cup, and I'm sure everyone else does, too," the 25-year-old attacking midfielder told local media this week at Japan's training camp ahead of his debut on soccer's biggest stage.

"But I don't want to get my priorities mixed up here – the important thing is for Japan to win at the World Cup.

"I'm not using the World Cup as a place to showcase myself for (van Gaal)."

Kagawa, twice a German Bundesliga champion with Borussia Dortmund, failed to score a goal in 30 matches he played for United in his second season at Old Trafford.

He figured in 18 Premiership games under Moyes, who took over from legendary Alex Ferguson at the start of the 2013-2014 season.

Van Gaal's appointment as successor to the sacked Scot has not fazed Kagawa who said it came as no surprise to the Red Devils.

"We've known for some time it was going to be him," Kagawa added.

"We've got the World Cup first so I'll deal with all that after this is over."

He will lead the Blue Samurai's attack along with AC Milan's Keisuke Honda in Brazil next month when they face Ivory Coast, Greece and Colombia in World Cup Group C.

It remains to be seen if Kagawa's chance of game time at United will improve under the Dutch disciplinarian against midfield rivals in the team such as Wayne Rooney, Juan Mata and Adnan Januzaj.

The Japanese star said the prospect of his first World Cup appearance had helped motivate him throughout the time he spent on United's bench.

"I basically want to keep doing what I did at Manchester United. I made sure I got the work in after games I didn't play in. I know how to get myself into shape.

"I was able to stay motivated despite the year I had because I had the World Cup to look forward to."