According to a union official, resolving the strike could depend on improving the pay conditions for NHS employees.
Giles George, an ambulance technician, claimed that shift workers received up to 20% more in pay, which they lost if they had to take a sick leave for six weeks.
Removing that, according to Mr. George, a GMB representative in Knighton, Powys, could "sway" employees who have already rejected a 3 percent offer.
The Welsh government declared that after other unions had had a chance to consider the pay offer, it would decide what to do next.
On the picket line on Monday, GMB ambulance workers will be joined by Unite-represented coworkers as part of a three-day walkout.
The GMB reported that 66 percent of its members voted against the offer for 2022–23, which would have added an additional 3 percent—of which 1 point 5 percent will be in pay each year—on top of the 4 point 5 percent, on average, that was paid to health workers last autumn.
According to Mr. George, changing some pay conditions had been discussed during negotiations with the government.
He said on BBC Radio Wales Breakfast, "It's unfair that you lose part of your pay if you become ill through no fault of your own.".
Some terms and conditions, according to Mr. George, have been in place for 20 years, and it is time for a change.
He claimed that similar discussions in Scotland included cutting the work week to 36 hours, which "would definitely persuade" coworkers who had previously rejected the most recent offer from the Welsh government.
According to the Welsh government, the offer, which amounts to a 3 percent increase in total compensation, is a compelling one.
"This is in addition to the already-awarded average pay increase of 4.5 percent for 2022–23.
"In our current funding settlement, this is the best offer we can present.
"In an effort to resolve the dispute, we have pooled all of the Welsh government's funding resources to make this improved offer.
"Before deciding what to do next, we will wait to hear other health trade union colleagues' opinions as they continue to discuss this offer. ".
After failing to secure a mandate for strike action the previous year, Unison, a third ambulance workers' union in Wales, is re-balloting its membership.
During the strike action from Monday to Wednesday, Sonia Thompson of the Welsh Ambulance Service urged the public to "only call us in a life or limb-threatening emergency."