Security patrols and sniffer dogs were deployed at dozens of Philippine airports Friday, after the aviation regulator received a bomb threat against commercial planes.

The Civil Aviation Authority of the Philippines said it was investigating the threat received via email warning that aircraft at Manila airport and four others would "explode".

The regulator said 42 commercial airports "are on heightened alert as of today, October 6", without saying when the warning was received.

"Immediate enhanced security measures are being implemented across all airports," it said in a statement.

Eric Apolonio, spokesman for the aviation authority, told AFP: "No bombs have been found".

He said that no flights were disrupted following increased security measures at the airports.

The Manila airport authority said Friday that "foot and mobile patrols are in place and K9 units are doing the rounds of the terminals as added measures to its already established day-to-day protocols".