The Ministry of Defence said the Sea King helicopter, which was carrying four crew members, made a controlled landing in a field near Ardrossan, Ayrshire, at about 11.25 am today.
A spokeswoman said: "We can confirm that a Royal Navy Sea King Mark 5 helicopter from HMS Gannet made a precautionary landing just north of Ardrossan in a field adjacent to the Ardrossan to Largs road at approximately 11.25am after a potential technical issue was identified by duty crew members.
"The landing was smooth and unhurried."
She said the aircraft was en route to training at the time.
The spokeswoman said: "At no time was there any danger to the aircraft, crew or the public. There are no injuries.
"The issue relates to observations noted by the crew of fluctuations in a temperature gauge.
"Members of Police Scotland attended the landing site to ensure that all was well. They have since departed.
"Members of local HM Coastguard are on scene to manage high numbers of members of the public who have stopped to take pictures and watch."
Engineers from HMS Gannet, the helicopter search and rescue base at Prestwick in Ayrshire, are on site assessing the aircraft.