The new US-built F-35 stealth fighter jet will not appear as planned at Britain's Farnborough air show on Monday but may still take part at the end of the week, organisers said.

The entire fleet of F-35s, set to become the backbone of much of the air defences of several Western countries, was grounded in the United States last week because of an engine fire.

"Unfortunately the F-35B Lightning II will not be displaying at the Farnborough International Airshow tomorrow, Monday 14 July," the organisers said in a statement.

"The aircraft is still awaiting US DoD (Department of Defence) clearance but we are hopeful that it will fly at the airshow by the end of the week."

The organisers said that while they were hoping for a "positive result" for an appearance later in the week, "we fully support the stance to never compromise the safety of either pilots or show participants".

The Lockheed Martin-manufactured F-35's first international appearance at the Royal International Air Tattoo in Britain last week was cancelled in an embarrassing setback for the costly programme.

Both the US Air Force and Navy last week ordered a halt to all F-35 flights following a June 23 engine fire on one of the planes, which at $400 billion (300 billion euros) is most expensive weapons project in US history.

A top Pentagon official said on Thursday that the fire was likely an isolated incident and not part of a wider problem.

Officials had viewed the July 14-20 Farnborough Show as a promising opportunity to show off the new plane before a global audience of potential buyers.

Britain has invested heavily in the jets, which are to be used on its new generation of aircraft carriers.