The head of the Election Commission has told the BBC the body needs more powers to act effectively, after controversies over political funding and donations.
The Electoral Commission regulates elections and party funding
Chief executive Peter Wardle said he had been asking for some time for more powers of investigation and sanction.
Former Lord Chancellor Lord Falconer said the commission had not acted with sufficient "decisiveness" at times.
Mr Wardle said it had ensured illegal donations were forfeited and had fined parties for late filing of reports.
The Electoral Commission, set up seven years ago to regulate elections and party funding, has been criticised by some politicians who say it failed to act quickly enough during recent controversies surrounding donations and loans.
Current investigations include donations made by proxy to the Labour Party and late-declared donations to Peter Hain's Labour deputy leadership campaign.
But the watchdog cannot fine individuals who register individuals late and can only fine parties a maximum £5,000. If it thinks further action might be justified it can refer cases to the police.
Mr Wardle told the BBC's World at One programme the commission had initially focused on making politicians and parties understand the new rules on party funding declarations.
He refuted claims it had been slow to act prior to the Peter Hain case - saying other cases had been looked at by the police, and it had been fining parties for late reports for some years.
But he said without wider powers of investigation, "it's going to be difficult for us to fully conduct the work that politicians and the public have a right to expect of us."
He said: "For example, if we've got suspicions about a donation, the person who received it must give us information - the person who gave it doesn't have to tell us anything. We want a change there.
"And secondly, we want a wider range of penalties and sanctions when the rules are broken ... so that the parties will face consequences every time there's a problem."
Earlier Lord Falconer told the BBC the watchdog had failed to "move with a sufficient degree of decisiveness in a number of areas" and could have been "clearer that things weren't right" over recent controversies.
He said the watchdog should be the "authoritative body" adding: "They should be the people who can decide whether or not to prosecute rather than the police or CPS because they should be the experts."
Last year a report by the committee on standards in public life recommended that the commission should narrow its remit, cutting back on public awareness work - which currently accounts for 25% of its £22m budget.
Shadow justice secretary Nick Herbert said the government had "dragged its heels" in responding to that report.
"The need is to restore integrity, both in relation to political donations and in relation to securing the integrity of the ballot," he said.
The Labour MP John Mann, who recently made a complaint about Tory MP Derek Conway's payments from his MP's allowance to his elder son, said the commission was "a bit chaotic".
"I don't think they've mapped out what their role is, I'm not sure that their powers are appropriate yet - I think there's too much confusion," he said.