Day-night Test matches have been given the support of the ICC's chief executive, Haroon Lorgat, but a five-day game under lights will only take place once a suitable ball has been developed.

"The lack of crowd attendance at many grounds around the globe is a cause for concern," Lorgat said at a Sydney press conference to mark the 100th anniversary of the ICC's founding. "In that was the possibility of exploring day-night cricket because there is no doubt James Sutherland [chief executive of Cricket Australia] has put that on the table."

Last month Sutherland said that playing under lights "might be the only way that Test cricket stays alive", with attendances reportedly in decline in the face of Twenty20's growing popularity. The biggest problem, for players and public alike, is replicating the visibility of a red ball at night while retaining its colour and characterisitcs. In one-day and Twenty20 cricket, a white ball is used which contrasts well against the coloured clothing, sightscreens and the night sky.

But it discolours easily and behaves differently than the red ball. As one scientist told Cricinfo in April, "the optimum would be to have one ball, of course, which behaved in the right way [for all cricket]", but this is easier said than done.

At the start of England's 2008 domestic season, the MCC trialled the use of a pink ball with some success, and last November Cricket Australia were given assurance by the country's government scientists that a suitable replacement for red balls would be possible.

Despite the concerns over the future of Test cricket, Australia is one of the few countries - England being the second - where attendance (and television audience) remains strong. David Morgan, the ICC president, spoke more optimistically. "If you ask the cricketers what they believe to be the apex of the game, those who play say it's Test cricket," he said. "I understand that TV ratings for Test cricket are very good."