NSW cop charged with drink-driving

A NSW Police probationary constable who was involved in a car crash was allegedly almost five times over the legal alcohol limit.

The 25-year-old off-duty police officer was charged with high-range PCA following the crash in Ashcroft in Sydney's southwest on Wednesday afternoon.

Police say the man is an off-duty probationary constable attached to a command within the South West Metropolitan Region.

He was taken to Liverpool Police Station where a breath analysis returned an alleged reading of 0.243.

Police Commissioner Karen Webb is "gravely concerned" about the incident, saying the officer had only been in the force for four months.

His driver's licence has been suspended and his job is on the line.

"His employment status will be reviewed today," she told Sydney radio 2GB on Thursday.

The matter will go before the court but the commissioner can take action to sack the officer without waiting for the outcome of the case.

"I don't know how you'd defend it," Ms Webb said.

"There's a process - I've got to serve him papers, he gets a chance to respond but I can start all of that and intend to start all of that before the court matter comes up," she said.

The officer was issued a court attendance notice for high-range PCA and will appear in Liverpool Local Court on December 14.