The presidents of the States' three biggest spending committees have written in support of the original tax and social security reforms from Policy and Resources.
Last week P&R published two alternatives to introducing GST which they said would be capable of fixing Guernsey's financial deficit over time by around £85m.
Those amendments provided deputies with three options to vote on:
Option A was their original proposal - including GST.
Option B looks at alternative revenue-raising measures without GST, such as paid parking and a 50% increase in property rates - TRP (tax on real property).
Option C prioritises cost-cutting, shaving £31m off spending on public services.
The public response online was overwhelmingly negative, as islanders accused the committee of presenting worse options to make GST appear more palatable.
The group of deputies behind the Fairer Alternative responded with their own new amendment.
"Option D" from Gavin St Pier, Heidi Soulsby and Sasha Kazantseva-Miller suggests the government approach this topic with a two-stage plan.
Starting with a £50m package of spending restraint and revenue raising, before launching an investigation into further spending and saving measures.
Deputies Al Brouard, Andrea Dudley Owen and Rob Prow have now come forward to defend P&R's original proposals - including GST - saying they are the fairest.
They are the president of the Health, Education and Home Affairs - the committees with the largest States spending.
In an open letter, the group says P&R is telling the truth - without action, essential services will suffer:
"Our experience shows us the States cannot currently keep up with the demand for the services that Islanders want and expect. We’re not talking about raising money so that the States can get bigger and provide all things, to all people; we’re largely talking about maintaining services as they become more expensive because more people need them.
There was no intention to frighten - it is an inescapable truth that we have a massive shortfall in public finances. The fact is that anyone who tells you that the States can save £31m a year (Option C in P&R’s alternatives) without a slash and burn approach to services is either incredibly misinformed or being economical with the truth."
They say campaigners have been swaying the conversation:
"We recognise that ‘No to GST’ has a certain allure. But it’s just a slogan. If P&R were simply proposing to introduce GST, none of us would support it. We suspect you’d struggle to find a single States Member who would. As a standalone tax GST is regressive and disproportionately impacts the poorest members of the community, but that’s not what is on the table."
An Anti-GST drive took place on Sunday for elderly or disabled islanders that couldn't attend the previous protests and march because of mobility issues.
The convoy of cars and a bus departed from North Beach, heading north in a loop around the island.
Another protest has been planned to take place outside the Royal Court building on Wednesday (15 February) at 8.30 as politicians continue the debate.
Guernsey's marine litter problem to be raised with UN agency
Guernsey's Occupation survivors to be honoured with special cobblestones
Parking to resume at the East Arm of Guernsey's main car park
Guernsey's population is at its highest ever