John Taylor, parliamentary secretary at the Lord Chancellor's Department, suggested that solicitors should be forced to tell their clients how much they were likely to charge.
His comments follow repeated criticisms that people are kept in the dark about the probable size of their lawyers' fees, only to be stung by a huge bill at the end of their case.
Speaking at a Law Society conference in Oxford, Mr Taylor also confirmed that the Government was preparing regulations to introduce a limited form of American-style no- win no-fee arrangements. Under this scheme solicitors will, in certain types of case, receive no money if they lose and a higher than average fee if they win.
Mr Taylor said he often received letters from people complaining that their solicitors had failed to tell them what sort of costs they could incur.
'The profession too often asks, as it were, for a blank cheque. There are still too many solicitors who make little or no attempt to explain to their clients the basis on which they will be charging,' Mr Taylor, who practised as a solicitor in Birmingham, said.
Some lawyers agreed to undertake conveyancing for a fixed fee, only to replace it later by a 'much more substantial fee'. 'Tales such as this smack of sharp practice rather than of professionalism . . . And those complaints will continue until the profession makes it a mandatory requirement that clients are informed of the basis of charging.'
He said when the Law Society decided one of its members had charged too much, the Solicitors' Complaints Bureau should be informed. At present, the bill is reduced but no action is taken against the lawyer.
His remarks echo a report last year by Michael Barnes, the Legal Services Ombudsman, who said solicitors often ignored professional guidelines to be open with their clients about fees.
Mr Taylor also outlined the the no- win, no-fee scheme. This will only apply to cases involving personal injury, insolvency and the European Court of Human Rights, and will enable lawyers to charge 20 per cent more than normal if they win.
The Government hopes that at a time of legal-aid cutbacks, the new system will give people who could not otherwise afford a lawyer the chance to go to court.
However, stumbling blocks remain, with many lawyers saying they will be reluctant to participate in the scheme. They say that since they will get no money if they lose, they should be able to demand more than a 20 per cent uplift for winning.
And, unlike in the US, the losers will still be expected to pay the other side's costs, so anyone who goes to court faces the prospect of paying out large sums of money.