Tennis officials have moved to target controversial mid-match first-round withdrawals at the grand slams.

With lucrative prizemoney on offer to those who exit at the first stage in the majors, the sport has been beset by injured players choosing to take their spot in the draw before pulling out. Under changes endorsed by the Grand Slam Board in London this week, unfit players will still be eligible to receive 50 per cent of the first-round prizemoney if they withdraw on-site after midday on the Thursday before the tournament. The "lucky loser" who takes their spot will be able to collect the remaining 50 per cent.

Nicolas Almagro was paid $50,000 for four games at this year's Australian Open. Credit:AP

In one case at January's Australian Open, former world No. 9 Nicolas Almagro collected $50,000 for playing four games of tennis, which lasted 23 minutes. At the time the Spaniard denied he had entered his first-round match believing he wasn't fully fit, despite admitting a scan taken the previous week confirmed he had injured his calf.

The crackdown is designed to ensure spectators aren't left disappointed by drastically shortened matches.