Companies that use automated dialling to solicit business, but which result in silent or abandoned phone calls, face fines of up to £2m from this week.
Ofcom welcomed Parliament's decision to increase its powers to levy fines from £50,000 to £2m.
Ofcom CEO Ed Richards said the increase reflected the potential seriousness of the harm caused to consumers by the "unsolicited and intrusive nature" of silent and abandoned calls. Last year Ofcom chairman Colette Bowe called for stronger powers to clamp down on silent and abandoned calls.
It has fined nine companies to date, including hitting Barclaycard for £50,000 in October 2008.
The regulator is looking to change its policy on abandoned and silent calls and may bring in new rules to address repeat silent calls and will publish a statement shortly.
Ofcom said it may also use its new powers to attack those who indulge in number scanning, withholding or providing misleading calling line identification, using systems for dishonest gain, and misusing allocated telephone numbers.