As per ITB document, endurance up to 30 days; 4,500 NM range @ 15kts cruise speed; EEZ protection; AAW-, ASuW-, ASW-, and EW-capable.
PROPULSION MACHINERIES: The vessel shall have a minimum two(2) main propulsion engines which are able to provide desired speeds each coupled with two counter-rotating propellers driven by a reduction gear box. All pr opulsion machineries can be operated using commercially available Philippine standard fuel. The engines shall be fitted with adequate safety monitoring and controlling devices for speed, temperature, pressure and other operational functions. The machinery installation should be suitable for operations
Propulsion isn't specified, though, whether diesel, gas turbine, or both.
Was this done purposely to make the requirement as generic as possible - meaning, PN might consider all turbine engines, too?