Associations including Chamber and GIBA say an amendment to the tax debate offers no alternative way of raising public money.
Deputies Liam McKenna and Simon Vermeulen's amendment to proposed tax reforms calls for no more work done to implement GST during this political term.
It comes as this week, the States will vote on whether to include food within the GST package.
It is part of an ongoing tax review that is exploring the options for raising public money and setting the groundwork for GST's introduction in 2027, along with a range of mitigating benefits.
But the Chamber of Commerce, the Institute of Directors, the Guernsey International Business Association and the Association of Guernsey charities want deputies to vote down the amendment.
They say it does not suggest a financially viable alternative and that the tax system and the looming deficit must be tackled.
Deputies McKenna and Vermeulen, alongside deputies Rob Curgenven and Haley Camp, gave a presentation over the past weekend on GST and its potential pitfalls. Around 100 people attended the talk at Les Cotils.
Former deputy Carl Meerveld, who says he will stand in the forthcoming by election if it goes ahead, outlined at the presentation why he opposes GST:
"You shouldn't be increasing taxes at all until you've dealt with the underlying problems in the organisation that is wasting more money than you are raising with GST."
You have to look for additional revenue sources but you also have to change the organisation to eliminate the losses inside."
A group, led by States chief executive Boley Smillie, is currently trying to find out why two States' IT projects, with a combined value of £42M, offered little in terms of value, and were branded by deputy Gavin St Pier a ''shocking waste of public money.'
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