The last government announced plans to increase the fines because of companies' use of automated systems which dial more numbers for marketing phone calls than there are operators to deal with them.
"Companies who make nuisance calls by abusing automated equipment should face the consequences, which is why those who break the rules will be fined with a hefty penalty of up to £2m," said the-then consumer affairs minister Kevin Brennan in March of this year.
The Conservative-Liberal Democrat coalition Government has implemented the change via a ministerial order signed by culture and communications minister Ed Vaizey on 15 September. It will come into force on 25 September.
Ofcom regulates the persistent misuse of telecoms networks, which is illegal under the Communications Act. Penalties for misuse were just £5,000 until 2006, when they were raised to a maximum of £50,000.
Barclaycard was fined the maximum £50,000 in 2008 by Ofcom in what the regulator said was "the most serious" case of silent or abandoned calls it had come across.
"Had we not been limited by the statutory maximum, we would have imposed a larger financial penalty to reflect this misuse," Ofcom chief executive Ed Richards said at the time.
Ofcom rules say that silent calls must not make up more than 3% of marketing calls in any given 24 hour period, and that the company behind the calls must be identified, even before an operator is available.