Short answer — there isn’t a single “best” package for every entity. Pick a platform that matches your organisation’s size, existing systems, who will own the work (finance vs. sustainability), and whether you need full carbon accounting, disclosures drafting, or audit/assurance support. Recommended vendors that are widely used or explicitly position themselves for AASB S2 / ASRS compliance:

• Sweep — strong data collection, pre‑configured AASB/IFRS templates, integrations and disclosure drafting tools for climate reporting. (Sweep.net)
• Workiva — mature reporting and controls platform with IFRS/IFRS‑SDS support and mapping for sustainability standards (can be used for AASB S2 alignment). Good where finance controls and auditability matter. (support.Workiva.com)
• Speeki / Greener / Greenbase / Emmi — Australian-focused solutions that explicitly advertise AASB S2 (ASRS) readiness, templates and local guidance (useful when you want Australia‑specific workflows and advisory). (Speeki.com)
• Carbon accounting / inventory engines often paired with a disclosure platform:
  • Persefoni, Envizi (IBM), Sphera, Emitwise, Normative — strong for Scope 1/2/3 calculations and integrations; pair with a disclosure engine for AASB S2 narratives and assurance. (Vendor pages for product details; pick based on integrations and scope coverage.)
• Specialist disclosure and assurance consultancies — many organisations combine a carbon engine + disclosure platform + Big‑4 / specialist assurance for the directors’ declaration and limited assurance requirements under AASB S2.

Why these choices:

• AASB S2 is the mandated climate standard in Australia (mandatory for in‑scope entities for annual periods beginning on or after 1 Jan 2025), so solutions that explicitly support AASB/IFRS S2 mapping and auditability reduce implementation risk. (aasb.gov.au)
• You’ll need both: (a) robust, traceable data collection and GHG accounting (Scope 1–3) and (b) narrative/disclosure drafting, taxonomy mapping, and evidence storage for assurance. The vendors above split across those two needs and many integrate with one another. (Sweep.net)

How to choose (quick checklist)

1. Coverage: Does the tool support AASB S2 / IFRS S2 mapping and the four pillars (governance, strategy, risk management, metrics & targets)? Look for preconfigured AASB/IFRS templates. (Sweep.net)
2. Data sources & integrations: Can it ingest finance/ERP energy bills, utility meters, procurement data, and upstream/downstream spend for Scope 3? (APIs, SFTP, connectors).
3. Carbon methodology: Does it use recognised emission factors (GHG Protocol, local factors) and support Scope 3 categories?
4. Auditability & controls: Versioning, audit trail, role-based access, and support for limited assurance engagements. (Sweep.net)
5. Outputs: Can it produce the climate statement, notes, and directors’ declaration in formats your board/auditor want? (Word, XBRL/IFRS taxonomy exports where required.)
6. Local guidance & support: Australia‑specific guidance, implementation consultants, or partner ecosystem (often important for first-year compliance). (aasb.gov.au)
7. Cost & scale: SaaS tiering, number of data feeds, user seats and professional services for setup and assurance.

Recommended combinations (common patterns)

• Large listed company / finance‑led: Workiva (controls + disclosure) + Persefoni / Envizi for carbon accounting + Big‑4 assurance. (support.Workiva.com)
• Mid‑market / Australia focus: Sweep or Speeki or Greenbase (AASB S2 preconfigured) + a carbon engine (Persefoni, Emitwise, Normative) if deeper Scope 3 needed. (Sweep.net)
• Smaller or first‑time reporters: Specialist Australian providers (Greener, Emmi, Speeki) that bundle readiness assessments, templates and training. (Greener.com.au)

Next practical step (one‑week plan)

1. Do a 2‑hour internal gap assessment: owner (finance or sustainability), systems (ERP, utilities, procurement), available emissions data, and assurance plans. AASB’s Knowledge Hub is useful background. (aasb.gov.au)
2. Run 2–3 demos with vendors that match your profile (include your auditor on the demo). Ask for: AASB S2 mapping, Scope 3 workflow, evidence/audit trail, and output examples (climate statement + directors’ declaration). (Sweep.net)
3. Pilot one business unit for 6 months to validate data flows, then scale.

If you want, I can:

• shortlist 3 vendors matched to your company size and current systems (tell me size, existing ERP/accounting system, who will own reporting), or
• prepare a templated RFP checklist you can send to vendors to compare features and pricing.

(Note: I cited AASB / vendor pages showing AASB S2 availability and vendor AASB‑focused claims. If you want vendor pricing or the absolute latest product features, I can fetch current vendor product pages or request demos.)