Pushed through by the Opposition with the support of Independent senators Nick Xenophon and Steve Fielding, the change in effect means the legislation is unlikely to be voted on until August.

And Senator Xenophon will attempt to formalise the delay today to allow more economic modelling and variations including higher emissions targets to be examined.

The delay comes after what Climate Change Minister Penny Wong said was a day ''debating what to debate'' on Monday, and could also deny the Government a double-dissolution trigger until at least December.

Senator Wong would not comment on whether she had received legal advice about whether the delayed vote on the Bills could constitute the first stage of a trigger.

But she attacked the Opposition for further delaying the Bills.

''This [is] how this alternative government fronts up to the important issue of climate change. Not even prepared to debate the Bill but prepared only to play political games and engage in political stunts in order to avoid making a decision,'' she said.

But Senator Xenophon said more economic modelling was needed before the legislation was brought to a vote. ''I don't take this issue lightly about rearranging the business but frankly the Government has failed.''

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