France's Thales reported strong first-quarter orders and sales led by its defence business as global tensions spur demand for air defences, but predicted growth would stabilise in the second half as it reaffirmed forecasts for the year.

Europe's largest defence electronics company said orders jumped 46% to 5.037 billion euros ($5.4 billion), buoyed by a third tranche of Rafale fighters for Indonesia, for which it makes the radar, and an air surveillance system for an unnamed Middle East nation.

Revenues rose by an underlying 7.9% to 4.421 billion euros, in part due to a favourable basis of comparison in defence and security which grew 13%.

"In the second half, (growth) will doubtless normalise," Chief Financial Officer Pascal Bouchiat told reporters.

On average, analysts were expecting quarterly orders of 3.65 billion euros and sales of 4.357 billion, according to a company-compiled survey.

($1 = 0.9343 euros) (Reporting by Tim Hepher; Editing by Sudip Kar-Gupta)