Voters will seek a clearer picture of ACT government vision in budget

The pieces it's already revealed amount to an unfinished jigsaw puzzle that suggests the government has largely shaped the 2017-18 budget around its election commitments, promises voters endorsed by handing Labor a fifth term in October.

While it's hinted at its priorities with early spending announcements, the projects it's decided to leave from the package say as much about its plan for the city.

There will be no money given to a business case for a new convention centre, an asset supporters say a city of Canberra's standing needs to compete on the national and international stage of meetings and conferences.

A $25 million spend on planning work for stage two of its ambitious light rail vision, which would extend the burgeoning network south to Woden, shows where the government wants to direct its energy and money.

Meanwhile the future of another major project, a new stadium, is unclear as the government raises the idea of buying Canberra Stadium for upgrades, and with the type of playing surface to be used and work to move Parkes Way set to complicate the expensive build.

Each project, a significant financial commitment, could transform Canberra in its own way but the benefits of light rail are perhaps more appealing and immediately clear to voters.

The government is backing off from the convention centre and is staking much on light rail. It appears to have calculated that drawing on federal support for only one major project will be more realistic.

Against expectations, the ACT government again looks set to forecast a return to budget surplus in 2018-19, albeit a thin one.

A relatively harmless federal budget has given the Barr government more financial room to move than in recent history.

Public service cuts didn't reach Abbott-era levels, although the outcome for Canberra of the federal government's decentralisation bid remains to be seen. Chief Minister Andrew Barr looks assured the ACT will be relatively unscathed, and is planning accordingly.

Aside from a string of budget announcements promising upgrades to playgrounds, pedestrian and cycle paths and bike tracks, what's been revealed so far leaves a few pressing questions about the ACT's problems unanswered.

The government could spend on a start to planning work for the new "SPIRE" building and emergency department at the Canberra Hospital, but will it do enough to turn around the troubled facility?

A plan to abolish stamp duty on some properties is, in part, a bid to address the ACT's growing housing affordability issue, but whether it will leave young homebuyers and disadvantaged people better off is far from clear.

Ultimately, whether Canberra can afford progress only on light rail while other major projects remain uncertain will be borne out by its future economic growth.

That's a question that won't be answered in Tuesday's budget.