The Prime Minister cited the delay in dredging Falmouth harbour as an example of how projects that could boost the economy are put in the "too difficult" box.
The £20million scheme is part of a wider masterplan for the port, but the Marine Management Organisation, which has to grant approval for the work, has so far blocked the scheme because of environmental fears.
It is currently the subject of a trial dredge to try and provide evidence that a full dredge to create a deep water channel will not have an undue effect on the seabed, in particular on maerl beds.
David Cameron told the Liaison Committee of MP'son Tuesday night: "Often the problem can be solved, but it's put into the too difficult box, like in the case of dredging Falmouth harbour, where we raise these things at cabinet level in order to try and get departments to bring up things that they are blocking and explain why they are blocking them and see if we can find a way through it."
