Sir Michael Rake, chair of the BT Group, said that payroll giving was the simplest and most effective way for employers and employees to give to charity.
"BT alone raises £3.5m for charities through payroll giving every year, but many more British businesses need to get behind the scheme if it is ever to truly deliver on its massive potential," he said.
Andy Harrison, chief executive of Whitbread, which owns brands including Costa Coffee and Premier Inn, said: "More than 20 per cent of our team members have chosen to donate regularly in this way because it's easy and tax-efficient.
"I would encourage every employer to be a force for good by helping their people support the charities of their choice in this way."
Their support comes in the wake of criticism of payroll giving. A report published last month based on comments made at a fundraisers summit suggested that payroll giving should be axed because it might no longer be "fit for purpose".
However, a survey commissioned by the payroll giving company Payroll Giving in Action and carried out by research company OnePoll, released yesterday, found that 61 per cent of people believe their employers should offer the scheme to staff.
The company polled 2,000 nationally representative British adults.