A spokesman for the Coastguard said they were called to reports of suspected ordnance at about 12:10. It is thought to be an old military device.
The public have been advised to stay away from the beach area.
A bomb disposal team is expected to attend the scene on Wednesday morning.
An area of Rosemarkie beach on the Black Isle, north of Inverness, has been cordoned off after an unexploded bomb was discovered.