The UK's tax collection agency is putting forth a proposal that all employers send employee paychecks to the government, after which the government would deduct what it deems as the appropriate tax and pay the employees by bank transfer.

The proposal by Her Majesty's Revenue and Customs (HMRC) stresses the need for employers to provide real-time information to the government so that it can monitor all payments and make a better assessment of whether the correct tax is being paid.

Currently employers withhold tax and pay the government, providing information at the end of the year, a system know as Pay as You Earn (PAYE). There is no option for those employees to refuse withholding and individually file a tax return at the end of the year.

If the real-time information plan works, it further proposes that employers hand over employee salaries to the government first. "The next step could be to use (real-time) information as the basis for centralizing the calculation and deduction of tax," HMRC said in a July discussion paper.

HMRC described the plan as "radical" as it would be a huge change from the current system that has been largely unchanged for 66 years. 

Even though the centralized deductions proposal would provide much-needed oversight, there are some major concerns, George Bull, head of Tax at Baker Tilly, told CNBC.com. "If HMRC has  direct access to employees' bank accounts and makes a mistake, people are going to feel very exposed and vulnerable," Bull said.

And the chance of widespread mistakes could be high, according to Bull. HMRC does not have a good track record of handling large computer systems and has suffered high-profile errors with data, he said.

The system would be massive in terms of data management, larger than a recent attempt to centralize the National Health Service's data, which was later scrapped, Bull said. If there's a mistake and the HMRC collects too much money, the difficulty of getting it back could be high with repayments of tax taking weeks or months, he said. "There has to be some very clear understanding of how quickly repayments were made if there was a mistake," Bull said.

HMRC estimated the potential savings to employers from the introduction of the concept would be about £500 million ($780 million).

But the cost of implementing the new system would be "phenomenal," Bull pointed out. 

"It's very clear that the system does need to be modernized… It's outdated, it's outmoded," Emma Boon, campaigner manager at the Tax Payers' Alliance, told CNBC.com. 

Boon said that the Tax Payers' Alliance was in favor of simplifying tax collection, but stressed that a new complex computer system would add infrastructure and administration costs at a time when the government is trying to reduce spending.

There is a further concern, according to Bull. The centralized storage of so much data poises a security risk as the system may be open to cyber crime.

As well as security issues, there's a huge issue of transparency, according to Boon.

Boon also questioned HMCR's ability to handle to the role effectively.

The Institute of Directors (IoD), a UK organization created to promote the business agenda of directors and entreprenuers, said in a press release it had major concerns about the proposal to allow employees' pay to be paid directly to HMRC. 

The IoD said the shift to a real-time, centralized system could be positive as long as the burden on employers was not increased. But it added that the idea of wages being processed by HMRC was "completely unacceptable."

“This document contains a lot of good ideas. But the idea that HMRC should be trusted with the gross pay of employees is not one of them," Richard Baron, Head of Taxation at the IoD, said in the release.

A spokesperson for Chancellor of the Exchequer George Osborne was not immediately available for comment.