Zawraq is reported to have made substantial improvement in his race against time to be fit for the Derby at Epsom.

One of the leading contenders for the premier Classic, the Dermot Weld-trained colt was found to be slightly lame after working on Tuesday.

Initial X-rays and scans suggested the injury was not serious and his leg has been iced during the last 24 hours.

Zawrag was given light exercise on Wednesday morning but a decision whether he lines up on Saturday has not yet been made.

"I have just spoken to Mr Weld and, in his words, the horse is 80 per cent better than he was this time yesterday," Angus Gold, racing manager for owner Sheikh Hamdan Al Maktoum, told Press Association Sport.

"They've taken him out this morning and he's walking sound.

"Leigh Roche, who has done most of the work on him, trotted him and he thought he felt 100 per cent.

"The vet was there and he said he could see he was still feeling it a little bit, but there has certainly been substantial improvement and it's a step in the right direction.

"They will now continue with the icing and he will be X-rayed again, just to check nothing more sinister has come to light.

"Being positive, if he canters and everything is fine, I would imagine he'll be declared."

Since the news of his injury, Zawraq has drifted from 9-2 to 7-1 while Giovanni Canaletto has been backed in from 16-1 to 6-1.

After Coral took a STG20,000 ($A39,440) bet on Golden Horn, the market leader firmed from 7-4 to 13-8.