Authorities could be forced to release people from jail within days due to the crisis over the striking down of laws enforcing suspended sentences.

Criminal defence lawyers have begun writing to the State claiming clients are being held unconstitutionally and asking for their sentences to be vacated.

A number of High Court writs alleging unlawful detention are also expected.

The development came as two people, a homeless mugger and a woman convicted of false imprisonment, who had been due to have sentences activated yesterday, were set free as a result of Tuesday's High Court ruling.

A solution to the deepening crisis has yet to emerge with the formation of a new government still in limbo.

Department of Justice sources said intensive efforts were being made to clarify whether legislation was needed.

Acting Justice Minister Frances Fitzgerald said emergency amending legislation could be introduced, possibly within days, but the matter remained under "urgent examination" by Attorney General Máire Whelan.

It comes after Mr Justice Michael Moriarty this week struck down Section 99 of the Criminal Justice Act 2006 following judicial review proceedings taken by six men.

He found that the instant activation of suspended sentences where a criminal is found guilty of a new offence was unconstitutional.

This was because they were not given the opportunity to appeal against their conviction for the second offence before being committed to prison.

The ruling has had two major effects. Firstly, it has raised the prospect that an unknown number of convicted criminals may have to be set free because they are being unlawfully detained.

Secondly, it has stopped courts from approving applications to activate the suspended sentences of people who have re-offended.

Solicitor Cahir O'Higgins, who represented one of the six men who took the challenge, said he had at least 15 clients who may be affected by the judgment.

"I have written to the State and have advised them of the difficulty and have given them a reasonable opportunity to address the matter," he said.

He said he was seeking to have those cases listed back before the courts again so requests could be made to vacate orders activating suspended sentences.

Separately, it is understood six other prisoners are preparing to take legal challenges in the High Court, claiming they are being unlawfully detained.

Aside from people who are already in jail, applications to activate suspended sentences are not enforceable as a result of the ruling.

Two such applications were dropped yesterday at Dublin Circuit Criminal Court alone.

One involved Sonia Eglinton, of Back Lane, Dublin, who was sentenced to four years in prison with two suspended in 2013 for falsely imprisoning a recruitment agency owner in their office while she looted the premises.

The other involved Karl O'Brien (21), a homeless man sentenced to four years with two suspended for mugging a UCD student in Dublin city centre last year.

A previous hearing heard how O'Brien had admitted to the mugging but said he had no memory of it as he was on a "two-day bender" at the time. He had 20 previous convictions at the time.

New legislation will be required to resolve the situation, which sources insist can be done "extremely quickly" and brought before the Dáil despite there being no formal government.

However, a potential stumbling block will be the passing of legislation through the Seanad.

Polling in the Seanad election ends on Tuesday with the election of 59 senators, but it is the responsibility of the Taoiseach to appoint the final 11 members.

However, without a government this cannot happen meaning the ability of the new Seanad to approve legislation will be in a "constitutional grey area".

Ms Fitzgerald said: "The Government will take all necessary action open to it to address the issues arising from Judge Moriarty's judgment."

She sought to play down fears there could be a mass exodus of prisoners from jails - but she admitted she expected criminals to seek release from prison.

Irish Independent