The Defence Force is resuming its search for two Kiribati fishermen who have been missing for five days.

The search crew aboard an Air Force Orion had to land empty-handed yesterday, after failing to locate the six-metre aluminium boat the fishermen were last seen on.

Air Commodore Andrew Clark says they're able to scout a far bigger stretch of ocean today.

He says they'll re-work the search area using the latest weather information before heading out.

He says it's likely the fishermen have had a technical problem, such as losing power to the engine and have been drifting since.