All eight ministers have refused to react to the Labour Party’s accusation that they behaved in an “arbitrary, insensitive and non-transparent” manner when they gave themselves a large pay rise three years ago.

Labour says the motion, expected to be debated in Parliament before the summer recess, will give MPs a chance to “disapprove of the insensitive, arbitrary and non-transparent behaviour of Cabinet”.

The Times last week sent questions to each member of Cabinet, including the Prime Minister, asking how they planned to vote on the motion or whether they would abstain.

It also listed the major issues associated with the controversial rise and asked each minister to respond. However, not one of them offered a reply.

This contrasts sharply with their response in January when The Times conducted a similar exercise and replies from all (including parliamentary secretaries) were forthcoming within a few hours.

They had been asked to react to criticism by Nationalist MP Jean-Pierre Farrugia over the fact that besides keeping their MP’s honorarium they also decided to raise this to €26,700 from €19,100 and began pocketing it at the new rate behind the back of other MPs, who were kept on the old rate.

In identical replies, each dodged Dr Farrugia’s criticism and justified the increase, saying this covered their parliamentary duties. They also said the remuneration had been discussed in the media since 2008, so it was public.

Only a few days later they were made to refund the difference they pocketed, keeping, instead, the honorarium at the old rate.

However, a number of issues that had not yet been made public at the time have recently made the issue of the rises decided by Cabinet and implemented even more controversial.

Firstly, when the changes were announced through a parliamentary question in Parliament, Finance Minister Tonio Fenech had said the Opposition Leader and the Speaker were also entitled to an honorarium. However, the Opposition Leader has since 2008 remained without it. And while former Speaker Louis Galea had received the honorarium, his successor, Michael Frendo, was made to choose between the honorarium and his private practice.

It also emerged recently that, besides the honorarium, the constitutional offices involved in this issue were eligible to a duty allowance of 20 per cent of their salary, which replaced an expense allowance of some €2,329. But while ministers and parliamentary secretaries immediately began receiving this added allowance – which exceeds €8,000 – the Opposition Leader only got the old rate.

And although Dr Galea received the new rate during his short term, Dr Frendo was kept in the dark and on the old allowance.

The Cabinet had also decided that the Opposition Leader and the Speaker should have their basic salaries increased, placing them on the same level as parliamentary secretaries (from 100 per cent of Scale 1 to 105 per cent). But while this was implemented for Dr Galea, the increase never materialised for Dr Frendo and Opposition Leader Joseph Muscat.

The new pay packets were decided in May 2008 but the changes were only communicated to the public late last year and, even then, issues such as the duty allowance were not explained.

The Times had asked whether the duty allowance was new or an increase of some other allowance, but no replies had been forthcoming.

There was also no mention of Dr Muscat and Dr Frendo being placed on an old pay packet or that Dr Galea was given different treatment.

The Nationalist Party has insisted ministers were only receiving a weekly increase of €367, when it turns out the actual figure is €500.

The case is being investigated by the Auditor General.