The results of rents to mortgages pilot studies in Milton Keynes and Basildon had been most encouraging, he said at the launch of a nationwide scheme.
However, only 67 tenants took up the offer in Milton Keynes during the seven month pilot period. And just 40 rents to mortgages sales have been made in Basildon since Feburary 1991.
Sir George said the pilots had been designed to test the practicalities of what was a complex scheme rather than achieve high sales.
But Pete Challis, housing chair at the Association of London Authorities, said for many tenants the scheme was meaningless, since anyone on benefit was automatically disqualified.
The government will be spending £450,000 promoting rents to mortgages, largely by means of radio and newspaper advertising.