Nicholas takes cricket commentary leave

Mark Nicholas' illness has forced the Channel Nine cricket commentator to take leave.

Nicholas left the MCG in an ambulance because of stomach pain on the first day of the Boxing Day Test.

After resting on day two, he returned to work on Wednesday.

But Nicholas fell ill again and had to return to hospital.

"Mark is taking leave to resolve his health issues," a Nine spokesperson said on Thursday morning.

"He wants to thank everyone again for their kind wishes and continued support."