Now that we have seen no government is ready to listen to IMO,ITF & other UN bodies, so these bodies have to think in different ways.One way is to liase with safety inspectors detain all or any vessel through PSC inspection in various ports of the world i.e. if any crew found to have exceeded their original contract by 3 months, the ship should be detained; as having crew mentally not ready to continue sailing is very unsafe. I think this has already started by some PSC authorities, but it should spread all over the ports in the world.
Second way , in dry bulk sector, to get the commercial operator involved,e.g if the operator is say ,Cargill & the crew from India then ask them to find cargo & fix vessel for the Indian ports, similarly if crew is Filipino then fix vessel and take the ship to Philipines where crew will have the option to get relieved in their own country.This way more and more crew can be relieved in their home countries (flight requirement is not needed).This will be an win win situation for all.
Third way, is to divert the ships to nearest port where flight option is available, so that crew change can take place.