The number of teams taking part in the 2019 World Cup hasn't been finalised, the International Cricket Council told AFP on Friday as it responded to growing criticism that its proposed cut risked damaging the sport's development.

Cricket chiefs have come under fire for their plan to reduce the number of teams involved in England in four years' time to 10 from the 14 taking part in the ongoing tournament in Australia and New Zealand.

But ICC chief executive David Richardson, in a telephone interview with AFP, said Friday: "I've learnt never to say never to anything. I'm sure the format of the next World Cup will be debated after this one has finished."

Ireland beat one of the elite Test match nations for the third successive World Cup when they defeated the West Indies by four wickets in their 2015 opener, while Thursday saw tournament debutants Afghanistan's astonishingly rapid progress continue when they defeated Scotland by just one wicket to record their first World Cup win.

"I'm pleased with the performances of the qualifiers so far, but the bigger tests are still to come," said Richardson.  

"The question is what do you want the World Cup to be? Do you want it to be a jamboree of world cricket or the pinnacle of the one-day game?"

"Heading into this tournament there was criticism that the format (where 14 teams are split into two groups of seven, with the top four in each pool qualifying for the quarter-finals) would leave us with a long group stage at the end of which the eight teams everyone thought would get through had made it into the quarter-finals."

Asked what his feelings were following the initially improved showing by the four associate sides -- Afghanistan, Ireland, Scotland and the UAE -- taking part at the World Cup, Richardson said: "There's a sense of relief. Our biggest concern before the tournament was that these teams would be uncompetitive."

Richardson said the thinking in reducing the number of teams had been motivated by the experience of the 1992 World Cup, when the tournament was last staged in Australia and New Zealand.

According to Richardson, the 1992 event had the "best format" of any of cricket's 11 World Cups, with the then nine competing sides all playing each other with the top four from the round-robin phase going straight into the semi-finals.

"The best format was 1992," said Richardson, South Africa's wicketkeeper at that World Cup. "You had nine teams, then the semi-finals. There was something up for grabs in every match."

However, Steve Waugh, Australia's former World Cup-winning captain, was among those concerned by a reduction in the number of sides competing at the 2019 World Cup, telling Friday's Sydney Morning Herald: "It is definitely important to have the minnow countries to grow the game in different markets.

"The World Cup of soccer has 32 countries. Cricket needs more than eight teams playing."