More than 75 different politicians have been paid in excess of €500,000 each in salary, expenses and other payments in just over three years in office.

A database of payments has been created by the RTÉ Investigations Unit.

It covers all of the myriad payments made to politicians since they took office following the last general election.

The money amounts to nearly €100 million in total.

It covers the period from March 2011 to July 2014 and this is the first time it has been made available in such detail.

The figures show that the country's 166 TDs have been paid €78 million, an average of around €470,000 each over the 41-month period for their work.

This equates to around €138,000 per year in salary, allowances and expenses.

However, some public representatives choose not to be paid expenses or certain allowances, and receive much less.

Another €19.82 million has been paid out to 60 senators, with each of them receiving on average €330,000 between March 2011 and July 2014. 

That equates to around €97,000 in total remuneration per senator per year.

Of the money made available to TDs, €22.9 million of it was paid out in expenses to cover the costs of their travel, accommodation and constituency spending.

The expenses figure works out at €34,945 per TD per year.

A further €6.04 million was paid in expenses to senators, according to the figures compiled.

This works out at €29,463 in expenses per senator per year.

More information on this story is available on the RTÉ Investigations unit website.

How the expenses work

Expenses are paid in two separate categories; the travel and accommodation allowance, and the public representation allowance.

Although the Government says publicly these payments are vouched, they are not accounted for in any way that can be examined by the media or public.

The travel and accommodation allowance is paid out on the basis of a "band" system, worked out according to how far the politician lives from their place of work in Dublin.

For TDs, the payment ranges from €9,000 per annum for those based in the capital up to €34,065 for deputies living more than 360km from Leinster House.

The payments are slightly smaller for senators and range from €5,250 to €29,565, again according to their geographical location.

This travel and accommodation is paid out on an entirely unvouched basis and takes no account of how a person travels - whether using public transport, walking, cycling, or sharing a car as some TDs are known to do.

It also takes no account of how much is being spent on accommodation in Dublin, whether hotels are used or if the politician already owns a property in the capital or can stay with relatives.

The second part of the allowance is paid out to cover the costs "incurred in the performance of his or her duties" as a parliamentarian.

The system is extremely complicated, so much so that the Oireachtas had to create a 28-page handbook to guide politicians through it.

Crucially, the Oireachtas and Government have repeatedly stated that this half of the expense regime is now completely vouched.

However, TDs and senators are not required to submit any receipts unless they are subject to a random audit.

The chance of that happening in any given year is just 10%, whereby an outside accountancy firm is contracted to carry out an examination of their files.

The documentation retained by the politician is not subject to Freedom of Information legislation and can never be examined by the media or members of the public.

Even if the politician is subject to the random audit, the receipts involved still remain largely private, never to be seen by anybody except the auditor.

A statement from the Oireachtas to the RTÉ Investigations Unit said they were the "administrators of allowances that are legislated for by the government of the day".

They said there was independent oversight of the vouching system through the outside independent audits that were conducted each year.

Meanwhile, the Government refused to ask ministers to give a breakdown of their mileage claims, arguing that even when they were shopping, at family outings, or attending sporting and cultural events – they could technically still be working.