Reforms go against principles of open and adversarial system of justice say campaigners, lawyers and MPs

Plans for secret hearings in civil courts being put before parliament on Tuesday "offend the principle of open justice", a prominent Conservative MP has warned the government.

Andrew Tyrie, the member for Chichester who is chair of the all party group on rendition, has challenged ministers to abandon the proposals which he says are more in tune with a dictatorship than a democracy.

His comments to the Guardian are further evidence of widespread unease among senior lawyers and constitutional experts over the justice and security bill, which has its second reading in the House of Lords on Tuesday afternoon.

Last week, the Lords' constitution committee, whose members include Lord Irvine, the former lord chancellor, and Lord Goldsmith, the former attorney general, described the expansion of secret hearings into civil courts as "flawed" and "unfair".

Ken Clarke, the justice secretary, has defended the bill as a necessary method of exploiting intelligence material in court cases while protecting it from general disclosure. The bill will introduce secret hearings, known as closed material procedures (CMPs) into civil courts where a defendant or clamant is not permitted to see all the evidence.

But a submission from the majority of special advocates, security-cleared barristers who appear in sensitive cases, have also described CMPs – which are already used in special immigration tribunals – as "inherently unfair".

Tyrie's comments add to the pressure on the Ministry of Justice to defend the reforms. "The changes introduced since the green paper flatter to deceive," Tyrie said.

"The crucial offence to justice remains. The most important of which is that material will be presented to the court without the claimant or even his lawyers being able to see it. Instead he or she will be represented by special advocates – who have told us it's inherently unfair.

"It also offends the principle of open justice. However the government describes this, others will, with some justification, be able to describe this as 'secret courts'. Secret courts and impunity for state officials involved in wrongdoing sound more like the tools of dictatorships than Britain.

"We would have found far less out about rendition [under the system proposed by the justice and security bill]. We wouldn't know that the UK facilitated rendition. The scope for the judges to decide whether or not here should be a CMP is much narrower than it has been represented [by the government]."

Tyrie is currently involved in legal action against the CIA and the state department in the US, in an attempt to uncover more information about rendition.

The civil rights organisation Liberty is planning a protest outside the supreme court to coincide with the second reading of the bill, deploying bouncers to emphasise that ordinary members of the public and claimants will be kept out of court by the new rules on secret hearings.

Liberty's director, Shami Chakrabarti, said: "We will never shine a light on abuses of power by turning British courts into secret commissions locked away from victims, the press and public.

"The House of Lords has an uncertain future but peers have their first opportunity to pass judgment on a bill that would put future governments above the law and leave the rest of us in the dark. This is a perfect opportunity to see the second chamber at its best, defending ancient freedoms and equality before the law."

The legal reform campaign, Justice, condemned the bill as "unfair, unnecessary and unjustified" and likely to "undermine public confidence in the administration of civil justice [as well as] damaging the credibility of our judiciary".

"That one party will present his or her case unchallenged to the judge in the absence of the other party and his lawyers is inconsistent with the common law tradition of civil justice where proceedings are open, adversarial and equal," Justice warned.

The bill, it said, would allow the government "to more effectively control the handling of information in cases against them involving national security". It added: "The government has produced no evidence to support the case for this fundamental reform. These measures are not justified on the grounds of national security."

On the question of whether a judge would have the final word, the campaign group believes that Clarke, has exaggerated the judiciary's role.

"In practice, the decisions allocated to the judge are very limited ," the campaign group said. "... If there is any evidence that there will be harm, the judge must order CMP. The deference afforded by the judiciary to the executive on questions of national security is well documented. It is highly unlikely that the court would challenge the evidence of the secretary of state on the degree of risk."