In an interview published in Saturday's Financial Times, Cable, 67, said change was inevitable.
"We're not going back to business as normal," he said.
"The banking sector is going to have to accept disciplines on the way it operates, regulatory disciplines, and there is going to be restructuring."
Cable said the government's independent review into splitting up the banks retail and investment arms could result in specific changes, even if only in Britain.
"We can't close down the possibility that unilateral action might have to be taken."
The commission's interim report is due within a year.
Cable, a Liberal Democrat politician who shot to prominence during the global banking crisis two years ago when he gained a reputation for economic sagacity for his no-nonsense warnings of looming financial peril, said the new government was determined to force the banks to lend more to business.
"The banks are just not performing."
Some bankers fear unilateral action by Britain to impose curbs will send clients abroad. The British economy relies heavily on the financial services sector.
In a separate interview in Saturday's Guardian newspaper, Cable said the Royal Bank of Scotland and Barclays Bank Plc should be broken up to safeguard the economy.
Cable is among the most outspoken critics of banker greed and excesses, and in the Financial Times interview said his plans to crack down on banks was "fully a joint exercise" with the Conservative finance minister, George Osborne.
The Conservatives and Liberal Democrats formed a coalition this week after the Conservatives narrowly missed winning an outright majority in parliamentary elections on May 6.
The center-right Conservatives are traditionally seen as friendly to banks and other financial institutions, but they are under pressure to get tough after state bail outs of banks hit in the 2008 financial crisis left Britain deep in the red.
The new government's top priority is to reduce a record budget deficit running at more than 11 percent of GDP.
Other policies include introducing a banking levy and reducing excessive bonuses.
On Wednesday the Bank of England called for "careful thought and discussion" in reforming the financial system, and warned against too much haste.
Cable is a former chief economist with Royal Dutch Shell.
