NSW Premier Mike Baird has fractured a vertebra after falling on a set of stairs at his home on Saturday night.

Mr Baird said he was facing a "slowish recovery" but would not need surgery.

A scan on Monday revealed the extent of the injury.

The Premier's office said some upcoming engagements would need to be cancelled, but the injury was not serious enough to prevent his attendance at Parliament this week.

Mr Baird used social media to joke about the injury, writing on his Facebook page:

"Note to self: when fetching a glass of water late at night, don't walk down the stairs in your socks with the lights out."

He encouraged his social media followers to make light of the accident.

"Yeah I know ... the punchlines for this pretty much write themselves," he wrote.

"Knock yourselves out (I almost did!)."

Mr Baird's office has confirmed he will be in Parliament this week for debate on controversial legislation to shut down the state's greyhound racing industry.

The legislation, which has already been passed by the Upper House, has caused divisions within the Liberal-National Coalition and sparked alleged death threats against Deputy Premier Troy Grant.

The bill is expected to go to a vote in the Lower House on Tuesday or Wednesday.