It is part of a plan to increase the popularity of the sport outside its traditional areas, including in South America. 

"We will double the number of teams because we want to promote hockey throughout the world," said Leandro Negre, President of the FIH.

"By having more teams in the World Cup, it will definitely make the sport more popular."

Negre added that hockey is more popular in Europe and Asia and "we want to make it big in South America also".

The World Cup, which was first held in 1971 for men and 1974 for women, takes place every four years.

The men's tournament has been dominated by a small group of countries, including Australia, who won the 2010 edition in New Delhi (pictured above). 

But, in the women's game, Argentina are one of the strongest countries having lifted the World Cup in 2002 and 2010. 

Argentina's women celebrate winning the World Cup for the second time in three tournaments at Rosario in 2010

Negre wants to see other countries from that region making an impact. 

"Mexico has a big TV audience and following for sports...it will be a good place to promote hockey," he said.

"It's also nice to see that Brazil, who are not a hockey playing nation, trying their level best to improve the standard of their men's and women's hockey teams for the 2016 Rio de Janeiro Olympics.

"This is good for the development of hockey in South America."

The venue for the 2018 World Cup still has to be chosen with Malaysia among the countries having already expressed an interest.

The host for the 2014 tournament is the Hague in the Netherlands, who were chosen ahead of London, and which will stage both the men and women's tournament for the first time since Utrecht in 1998.

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