Racing is expected to go ahead at Warwick Farm on Wednesday with rain easing in south-western Sydney.

Racecourse manager Mark Jones downgraded the track to heavy on Tuesday afternoon after an additional 12mm fell on top the 18mm overnight.

But Jones said most of the rain was falling north of the racecourse which was receiving only light showers.

He advised Racing NSW stewards he was confident the meeting would go ahead with a favourable forecast.

There will be a further inspection of the track at 6am.

Elsewhere, barrier trials at Rosehill on Tuesday morning were called off after four heats while the last two races at Muswellbrook were abandoned because of the rain.