Here's what you need to know this morning.

Teacher's strike to go ahead

The NSW Teachers Federation says a strike planned for next week will go ahead, despite the Industrial Relations Commission demanding it be called off.

Public school teachers across the state voted on the weekend to strike on December 7 over pay and staff shortages.

In a ruling last night, the commission ordered the federation not to strike and to issue a public statement revoking its direction to strike by 4pm today.

But Teachers Federation president Angelo Gavrielatos said teachers had been left with no choice but to proceed with the industrial action because the government was not listening to their concerns.

"The teacher shortages are too large and their cause — uncompetitive salaries and unmanageable workloads — [are] too great for teachers and principals not to proceed with this action," he said.

In a statement, NSW education secretary Georgina Harrisson called on the federation to follow the directions and "put students first".

"Parents want their children in school and no-one needs another day out of the classroom after such a disruptive year," she said.

Calls to remove covert mobile speed cameras

The NSW Labor Party is supporting a push to return warnings signs to mobile speed cameras.

In November 2020 the NSW government announced warning signs would no longer be displayed on speed cameras, saying operations should not be highly visible to "generate an anywhere-anytime expectation of detection".

A NSW parliamentary inquiry is now investigating the viability of unmarked speed cameras.

Former roads minister Duncan Gay, who worked to make cameras more visible, said the government made the wrong decision to move to a more covert system.

Shadow Minister for Roads John Graham said the current rules were not supported by the public and suggested removing the signs was a "revenue-raising" measure.

Search for Revelle Balmain

NSW Police will carry out forensic searches today as part of continuing investigations into the disappearance of model Revelle Balmain, who vanished 27 years ago.

Ms Balmain was 22 when she disappeared in the Kingsford area, in Sydney's eastern suburbs, in 1994.

Personal items belonging to the part-time escort — including a make-up bag, keys and a shoe — were found scattered near Ainslie Street in Kingsford after she disappeared.

Police say they are exploring multiple new lines of inquiry, with searches set to take place at properties in Bellevue Hill, Bondi Beach and Potts Point.

No-one has been charged in relation to her disappearance. However a coronial inquest in 1999 found Ms Balmain died at the hands of a person or persons unknown.

In May this year the NSW government announced a $1 million reward for information that assisted investigators with their inquiries. 

Man charged over theft of John Oxley's watch

A man has been charged over the theft of a rare 19th-century gold seal from an exhibit at Parramatta in Sydney's west.

In May this year, explorer John Oxley's fob watch was taken from its exhibition case where it was being displayed at Old Government House, Parramatta.

The gold seal is made of engraved rock crystal and is mounted in an 18-carat gold converted fob watch.

A 43-year-old man faces multiple charges, including damage property by fire or explosion.

The gold seal has not been recovered.