Chancellor George Osborne has said "credit easing" – a move aimed at cutting the cost of borrowing for hard-pressed businesses – would be triggered.
The strategy would involve the public sector buying bonds issues by companies, was "potentially very significant" but full details would not be revealed until the chancellor's autumn statement in November.
In his speech, Mr Osborne said he had "thought hard" about what more can be done to boost growth and explored "every single option" - but "borrowing too much is the cause of Britain's problems, not the solution.
He added: "I'm a believer in tax cuts - permanent tax cuts paid for by sound public finances.
"Right now, temporary tax cuts or more spending are two sides of exactly the same coin, a coin that has to be borrowed - more debt that has to be paid off.