By Mark Potter

LONDON (Reuters) - Nike, the world's largest sporting goods maker, will extend its lead in sales of soccer-related products over rival Adidas helped by new launches and a marketing blitz at this summer's FIFA World Cup, its chief executive told Reuters on Wednesday 25 February.

Mark Parker also said that consumer confidence remained fragile and forecast a "long gradual" recovery.

However, he added that Nike was taking market share from competitors and seeing a "slight improvement" in orders, including a "significant" pick-up in demand for soccer-related footwear, clothing and equipment.

"We're entering a period where we are going to extend our leadership further (in soccer). So the World Cup is a great opportunity to see that happen, certainly (with) the product we're creating and the presence we will have," he said in an interview.

Parker did not give market share or soccer sales figures for Nike.

Parker was speaking as Nike kicked off its World Cup campaign with the launch of the latest incarnation of its hi-tech Mercurial soccer boot and a new addition to its Nike Football+ online soccer training tool.

On Thursday 26 February the group famed for its swoosh logo and "Just Do It" slogan will unveil kits for the 10 teams it is sponsoring at the World Cup finals in South Africa, which start in June.

Nike, the undisputed market leader in athletics and basketball, has been stepping up its presence in soccer, which is the world's most popular sport and expanding rapidly in developing markets.

It bought England team sponsor Umbro in 2007 and a year later wrestled sponsorship of the French team -- starting in 2011 -- from Adidas to add to a stable which also includes Brazil, Portugal and Holland.

However, it has a fight on its hands.

BACKING SOUTH AFRICA

Long-time market leader Adidas is sponsoring 12 of the 32 World Cup finalists, as well as the event itself, and also is providing kits for FIFA officials, and providing match balls.

The German group, whose teams include Argentina, Germany, Spain and hosts South Africa, also has said it expects record sales of soccer-related products this year, beating its previous high-mark of 1.3 billion euros ($1.8 billion) in 2008.

Parker was confident of success for Nike, saying it would launch more soccer-related products in footwear and clothing in the run up to the World Cup and also conduct an unprecedented marketing campaign at the month-long event.

He declined to give further details.

Parker brushed off fears that Africa's first ever World Cup might not have the sales potential of an event held in Europe.

"We're very happy it's in South Africa ... We feel very strongly this is going to be our best World Cup ever," he said.

On Tuesday 23 February, FIFA denied reports it would cut ticket prices or give away seats because of sluggish sales.

He said the U.S. group would launch a product "sooner rather than later" in the fast-growing market for toning shoes, which manufacturers claim can help tone muscles while the wearer is working out.

(Reporting by Mark Potter; Editing by Carol Bishopric)