A thunderstorm has curtailed the midweek race meeting at Warwick Farm.

The sixth race of nine on Wednesday's card - a benchmark handicap over 1000m - took place against a backdrop of thunder and lightning and then rain intensified, forcing officials to initially delay the program.

With lightning still apparent in the area, the delay was announced at 4pm, 10 minutes before race seven was scheduled to jump.

Jockeys then expressed concern about the track conditions, prompting an inspection by stewards and senior rider Hugh Bowman which led to the rest of the meeting being called off.

"We looked at the track, walked down to the home turn where they (jockeys) believe those issues lay," Racing NSW deputy chief steward Philip Dingwall said.

"The stewards concur, there is surface water at that point."

Dingwall initially hoped the meeting could resume but the weather showed no signs of clearing and the track was downgraded to a heavy 10 before the final three races were put on hold.

A decision on whether those races can be accommodated is expected later this week.