When ACT Greens backbencher Andrew Braddock agreed to support a push from the Gungahlin community to halt land sales in the town centre it set off sirens among Labor members.
The petition from the Gungahlin Community Council said residents had "completely lost confidence" in the planning system.
It called for land sales to be stopped until a proposed territory plan variation for the town centre had been reviewed by the Assembly's planning committee.
Mr Braddock also brought a motion to the Assembly calling on the government to halt future land sales until the planning variation had been made.
This forced Labor and Greens members into a bind.
Planning is a contentious issue and while both Labor and the Greens support urban infill, it is an area where parties have differing views.
The Greens caucus decided to support Mr Braddock's motion, with leader Shane Rattenbury saying there needed to be a "dynamic and high-quality plan for the Gungahlin town centre".
But Labor was not going to support the motion as presented.
A vote was not going to be a good look.
Housing Minister Yvette Berry had earlier invoked the Labor-Greens power-sharing agreement, which has pledged to build 600 affordable or community housing properties and 400 public housing properties over the next five years.
The agreement also says 70 per cent of future development would be urban infill. The Greens supported an even higher rate of infill at the election last year.
The agreement says this will be difficult to achieve due to "significant challenges in land availability, industry and sector capacity to deliver additional housing".
Labor and the Greens had been locked in negotiations over the motion for the past week but by Tuesday afternoon, when the motion was due to be presented, an agreement had clearly not been reached.
If the Greens had agreed to a significantly watered-down motion they would have been labelled as sell-outs.
If Labor agreed to support the motion they would be voting against their own policy.
It would have been extraordinary if the motion had been successful supported by Liberals and the Greens.
So when it emerged, rather coincidentally, on Tuesday afternoon there might be a possible conflict of interest with the Assembly's planning committee members, it was an opportunity too good to pass up for Labor and the Greens.
They could simply use this to defer the vote and give themselves more time to negotiate.
Slight cracks have already appeared over planning in this term, such as when Greens minister Emma Davidson threatened to cross the floor if a proposal to build a car park on land near Cooleman Court was not withdrawn.
But at the heart of this is a community fed up with a planning system that even the territory's head planner says gives developers a "clear pathway".
With a new planning system at least 18 months away, Labor and the Greens will have to work out how to work together on these inevitable clashes.
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