Labor has questioned Bob Day's decision to remain in parliament until the end of the year after the Family First senator initially said it would be "untenable" to stay.

The furore comes as Family First revealed it had put Senator Day’s replacement on hold as he had told the party of a “new potential investor” for his housing businesses. Senator Day, whose Home Australia group is in liquidation with more than 200 houses left unfinished, said on Wednesday he…