Ships of over 7,000 tonnes cannot berth around Tower Bridge because there are no facilities for passengers to disembark.
Two previous pier schemes - at Butler's Wharf and Jacob's Island - foundered when the property boom collapsed, and the plans were shelved.
The PLA's new chairman, Sir Brian Shaw, said yesterday that he hoped to stimulate a new initiative: 'We need somewhere where the boats could dock within sight of Tower Bridge. The tourists would be able to wake up and see it through their portholes. This is a major tourist opportunity.'
At the moment, boats can moor next to HMS Belfast near Tower Bridge but it is difficult for passengers disembark. Next year the PLA intends to dredge the river to ensure that boats of up to 10,000 tonnes can reach Tower Bridge.
Sir Brian said: 'We want to attract ships which are doing cruises such as the tour of European cities.'
Private developers, however, are unwilling to come forward because of the depressed state of the property market.
The PLA, which is funded largely by fees from river users, is itself unwilling to invest the money in facilities because of the risk.