The business secretary defended his upcoming conference speech as "pro-business" and "pro-market"
<!-- END - caption -->Vince Cable is to launch an outspoken attack on City greed and self-interest later as he seeks to soothe Lib Dem concerns about the coalition.
The business secretary will tell his party's conference that "murky" corporate practices threaten UK firms and "capitalism kills competition".
He will announce a consultation into issues such as executive pay and the role of directors in takeover battles.
Employers group the CBI accused Mr Cable of using "emotional language".
The CBI's director general Richard Lambert said Mr Cable had "harsh things to say about the capitalist system".
But Mr Cable defended his speech on the BBC's Breakfast programme, saying he was "pro-business, pro-market".
"I want to protect consumers, I want to look after shareholders, I want to level the playing field for small business," he said.
His speech comes amid renewed warnings from senior Lib Dem figures, including Mr Cable, about clamping down on excessive bank bonuses.
However, on Tuesday night Lord Turner, the chairman of City watchdog the Financial Services Authority, entered the debate about possible reform of the City, saying that while bank bonuses had contributed to the financial crisis, they had not been its main cause.
He said there was a need to "move beyond the demonisation of overpaid traders", and instead pointed to financial regulation which had failed to recognise and address the dangers in the financial system.
Even before he delivers Wednesday's speech, Mr Cable has responded to criticism levelled at him after excerpts were released in advance.
BBC political editor Nick Robinson said Mr Cable had told a fringe meeting at the Lib Dem conference on Tuesday that the speech had been wrongly "interpreted as an outburst of Marxism" and that he had needed "to go round explaining that that's not what I meant".
He added that Mr Cable said he had used phrases such as "I am shining a harsh light into the murky world of corporate behaviour" only to enliven the debate.
With deep spending cuts looming, the Lib Dem leadership has been under pressure to spell out how the least well-off will be protected and the wealthiest made to pay their fair share during the four-year process of reducing the deficit.
On the closing day of the party conference in Liverpool, Mr Cable will say he is prepared to intervene to tackle short-termism and "irrational" behaviour in the City when it damages the wider economy.
He will announce a wide-ranging consultation on executive pay, the role of directors and investors during takeover battles, and how shareholder influence over corporate decisions could be increased, saying the owners of businesses must act "responsibly".
"The government's agenda is not one of laissez-faire," he will insist.
"Markets are often irrational or rigged, so I am shining a harsh light into the murky world of corporate behaviour.
"Why should good companies be destroyed by short-term investors looking for a speculative killing, while their accomplices in the City make fat fees?
"Why do directors forget their wider duties when a fat cheque is waved before them? Capitalism takes no prisoners and kills competition where it can."
Rules regarding takeovers of British firms and the role of shareholders and managers are being reviewed amid concerns - sparked by last year's takeover of confectionary firm Cadbury - that British firms are too vulnerable and can be swallowed up without guarantees about jobs and investment.
In his speech, Mr Cable will also make a robust defence of the Lib Dems' support for spending cuts, saying the public are aware of the difficult financial situation and "sympathetic" to the coalition's argument that urgent action to reduce spending is necessary.
The proposed cuts are "bound to hurt", he will say, stressing that "strong disinfectant stings".
Mr Cable's attack on the banks is likely to alarm Conservatives also concerned that the City continues to be demonised for its role in the financial crisis at a time when it must play a vital role in sustaining the recovery.
The CBI's director general Richard Lambert said Mr Cable was right to call for shareholders to act in the wider public interest, but he added: "It's odd that he thinks it sensible to use such emotional language.
"The case for corporate takeovers is that they allow control of poorly run businesses to pass into more efficient hands. Mr Cable has harsh things to say about the capitalist system. It will be interesting to hear his ideas for an alternative."
On Tuesday Mr Cable had suggested a tax on bankers' pay and profits could be introduced if banks continued to pay huge bonuses to their staff, suggesting that a combination of tax, regulation and transparency could be designed to curb banks' behaviour.
Earlier in the week the Lib Dems promised a "ruthless" crackdown on tax evaders, saying their behaviour at a time of austerity was "morally indefensible".