"Tiger" kidnapping suspects could be questioned for a week under new legislation to be published today by Minister for Justice, Equality and Law Reform Michael McDowell.
The legislation will also require judges to impose mandatory 10-year minimum sentences on criminals found in possession of more than €500,000 worth of drugs.
Gardaí investigating drug trafficking can already hold suspects for seven days.
However, this is now to be extended to murder cases involving firearms, "tiger" kidnappings and cases where guns are used to endanger lives.
Judges and juries will be able to draw an inference from an accused's silence, in line with the recommendations made in the Balance in the Criminal Law Group's interim report.
"New cautions will be included which will make it perfectly clear that withholding information in certain circumstances may be taken into account in determining guilt or innocence," said the Department of Justice.
The Minister for Justice intends that the legislation will be debated by the Dáil next week on foot of its return from the St Patrick's Day break, despite Opposition charges that he is being too hasty.
Bail will become much harder to obtain, since Garda superintendents will be able to argue that it should be refused if they believe that suspects would commit serious offences if freed.
Bail hearings will have to take place before the Circuit Court, except in cases where the offences are triable in the High Court such as firearms, hostage-taking and drug trafficking.
Bail applicants will have to give details of their assets, income, previous criminal record and full details of any offences committed while on bail under the Criminal Justice Bill 2007.
However, Mr McDowell's decision to force judges to impose 10-year prison sentences on major drug criminals is "an attack on the judiciary", former High Court judge Feargus Flood has said.
Mandatory minimum sentencing, which will eliminate judges' ability to impose lesser sentences in "exceptional" cases, is "an attack on the fairness and individuality of those who administer justice", said Mr Justice Flood.
"The provision of the Constitution, Article 35(2), provides all judges shall be independent in the execution of their judicial function and subject only to this constitution and the law," he told Newstalk's Lunchtime with Eamon Keane.
"These are the parameters which members of the judiciary are confined and which they must respect.
"They are entitled to be independent in the exercise of their judicial function . . . Mandatory sentencing per se is an infringement of their judicial function," he said.
