People on benefits who are fined in court could face a fivefold increase in the amount docked from their weekly payments to cover the penalty, David Cameron will announce on Saturday as the government response to the riots is intensified.

Under the plans, the maximum weekly payment taken from benefit payments to pay off fines will rise from £5 to £25.

Cameron has been pressing hard for a series of measures to crack down on benefit recipients who commit crimes in the wake of the disturbances. Figures from the Ministry of Justice showed that more than a third of those who appeared in court after the riots were on benefits, including more than 200 on disability benefits.

Cameron will say in Perth: "People need to understand if they commit a crime they will face the consequences. The system as it stands at the moment is far too soft and does not send the right signal.

"Iain Duncan Smith, [the work and pension secretary], and I are determined to see responsibility and fairness restored to the welfare system and this policy does precisely that. If you commit a crime and are on benefits you can no longer expect to get away with paying the bare minimum."

Duncan Smith's Department for Work and Pensions (DWP) had been wary of increasing the amount taken from people's benefit payments if they are fined. It was concerned that people should not be fined twice – once by the court and once by the department as benefits are docked.

There could also be a danger that the DWP's legal requirement to provide benefit recipients with a defined level of support could be jeopardised.

But the concerns appear to have been overcome because the amount of money that will be docked from a recipient's benefits will be decided by the courts.

Duncan Smith welcomed the change. "I want to see responsibility and fairness restored to the welfare system and there can be no clearer example of this than when someone has committed a crime that they face losing a significant amount of their benefits," he said.

"The summer riots showed that, for many people, the present system didn't make them think twice about what they we're doing. The prime minister and I were clear we would look at all parts of the benefits system so they would feel the full effects of their actions.

"I do not want to be in the business of leaving people without means of supporting themselves. But equally individuals must know that they cannot commit crimes that impact on livelihoods and communities of hardworking people without consequences."