Labor wants a national corruption watchdog operational by the middle of next year, despite a push by Opposition Leader Peter Dutton and the Greens for a more powerful model to be adopted.

Attorney-General Mark Dreyfus said on Wednesday a taskforce within his department was already at work on the design of the new commission, which he says will have retrospective powers to investigate corruption in government and jurisdiction to consider political misuse of government grants – so-called pork-barrelling.