Plans produced by an international company show how the tax could work and how much the implementation of the scheme will cost.

The States employed company Crown Agents to come up with plans to cover the financial shortfall when a zero- rate corporation tax comes into force.

Formal proposals for a goods and services tax are expected to be put to the States in the next few weeks.

The final report has taken three months to complete and Steven Lowthorpe, the company's taxation director, says there will be other costs as well as those for setting the scheme up.

He said: "I think the big cost will be the recurrent expenditure.

"We've recommended the income tax department would administer the goods and services tax (GST), but we've estimated it would probably mean 10 additional staff."

There has been much controversy over the proposed 5% levy, which could be introduced as early as 2007.

The tax is aimed at correcting a budget deficit in the island which is also introducing a zero rate corporation tax.