Todd Barclay has been working in his electorate office on constituent matters, National says - as Winston Peters criticises the handling of his employment as "rotten".
Barclay, 27, hasn't been at Parliament since announcing last month he would not seek re-election as the Clutha-Southland MP, after allegations he secretly recorded a staff member during an employment dispute.
Parliament is currently in recess but will return next week.
A spokeswoman for Prime Minister Bill English referred questions about Barclay to senior whip Jami-Lee Ross, who said no decisions had been made about whether Barclay would return for the final four sitting weeks before September's election.
"As the party whip I am in regular contact with [Barclay] ... he has said he is keen to continue to work as MP for Clutha-Southland until the election and I am aware that he has been working in his office as the local MP on constituent matters."