Justice Minister Rob Nicholson announced on Tuesday that the Truth in Sentencing Act has now come into effect. (Chris Wattie/Reuters)

Federal legislation limiting the amount of credit prisoners can get for time served in custody before and during their trial has become law, Justice Minister Rob Nicholson announced on Tuesday.

"The two-for-one credit is no longer an option. This will bring more truth in sentencing and give Canadians confidence that justice is being served," Nicholson told reporters in Ottawa .

The Truth in Sentencing Act was actually granted royal assent on Oct. 21, 2009, but came into effect on Monday.

Nicholson said it usually takes around six months for a law to come into effect because it takes time to get the information out to all the provincial attorneys general.

It had been common practice among judges to reduce prison sentences by two days for each day a person spent in jail while awaiting trial and sentencing. In rare cases, the ratio was three-to-one if their detention conditions were deemed particularly difficult.

The new legislation means that as a general rule, the amount of credit for time served will be capped at a ratio of one-to-one.

It will permit judges to give credit at a maximum ratio of 1.5-to-one only when circumstances justify it, and they will be required to explain what those circumstances are.

No change in the one-to-one ratio will be allowed under any circumstances for people who have violated bail conditions or who have been denied bail because of their criminal record.

Pamela Stephens, a spokesperson for Nicholson, said the Minister of Public Safety has given assurances that space is adequate to accommodate the added demands on the system imposed by the new legislation.