A quarter of chief executives face a 24 per cent increase in their tax burden following the introduction of PAYE and PRSI on benefits from January 1st, according to PricewaterhouseCoopers.

Calculations by PwC also suggest that employers' PRSI on company cars will rise by €1,700 from the start of the year.

The company made its predictions as it unveiled a survey of chief executives' and head of units' benefits, which it says will allow senior managers compare their packages with industry averages.

Of those surveyed, 97 per cent of organisations provide either a defined benefit or defined contribution pension scheme to chief executives (or unit heads), with 4.3 per cent offering both.

Nearly 22 per cent of those with defined contribution schemes are non-contributory, while average employee contributions for defined benefit and defined contributory schemes are 7.2 per cent and 6.7 per cent respectively.

When calculating pensionable salary, 69.6 per cent of firms only take annual base salary into account, while 21.7 per cent take base salary plus variable pay. The remainder take into account "other elements" - defined as base salary less State pension.

The average retirement age of chief executives is 60, with the majority offered early retirement at 50.

Some 83 per cent of companies provide long-term disability benefits. Of those that do, nearly 60 per cent of respondents said the level was 67 per cent of salary.

Almost 96 per cent of participants provide death in service - 35 per cent of this as lump sum only. In 58 per cent of cases, lumps sums are four times salary.

Ninety-eight per cent of participants have a car or receive car allowance; 21 per cent have a choice of car or allowance; while 59 per cent have a car only. The average market price of car provided is €53,405, while allowances amounted to €15,344 on average. Popular models included Mercedes, BMW, Volvo, Lexus and Citroen.

Just over half - 54.5 per cent - of cars are leased, 36.4 per cent are bought outright, 6.1 per cent are lease-purchases, 3 per cent belong to car ownership schemes.

The majority - 77 per cent - of companies provide subsidised health insurance, with 81 per cent opting for VHI and 14 per cent for BUPA. Only 2.8 per cent offer a choice between the two.

Fifty-seven per cent of companies have at least one type of share scheme, with 92 per cent of these operating a share option scheme. Average annual leave for chief executives is 24 days, with 30 days the maximum.

The survey, conducted among 45 organisations in the Republic, underscores the growing significance of benefit packages for senior managers, said Mr Mark Carter, partner at PricewaterhouseCoopers.

Participants were drawn from major sectors, including financial services, construction, IT, telecoms, pharmaceuticals and healthcare.