National MP Judith Collins wants her Cabinet job back.
The Papakura MP resigned from Cabinet after emails surfaced which suggested she took part in a smear campaign against then-Serious Fraud Office director Adam Feely in 2011.
She stayed on as a senior minister after her resignation from Cabinet.
Ms Collins told TVNZ's Q+A that the allegations that led to her resignation had been disproven.
She said she had made it very clear she wanted to be in Cabinet - but that decision was up to the Prime Minister.
But she told the programme she had had no timeframe on when she should be returned to Cabinet.
Mr Key says he does not rule out putting the MP back into Cabinet but it is a matter of when a position becomes available.