"We don't think it's fair, we think it's discriminatory, we think that it's a barrier to people with disabilities, and it's unnecessary - it is not such a high cost that the Speaker and Parliamentary Service could not cover that at least until we get proper captioning.''
At a press conference this afternoon, Dr Smith said he was "astounded'' by the party's reaction.
"The Parliamentary Service has put a lot of work into providing Mojo with the technical equipment necessary to help her fulfil her role,'' he said.
"She's been provided with rather different technical gear, with laptops that employ software to provide for note-takers to provide as near as possible to real time presentation of what is going on.''
Dr Smith said while Parliamentary Service paid for the technological support, the actual note-taker was a staffing cost, and he did not have the authority to approve such funding.
"Staff time like that, or support like that, is not something I can just ask the Parliamentary Service to provide,'' he said.
"Support for Members of Parliament is something that's spelt out in the Speaker's directions, its separately appropriated by Parliament. I can't, under the law, simply say 'oh, forget about that, we'll put a bit of money in from here or there', it's something I have to consult on.''
Dr Smith said the issue was on the agenda for next month's Parliamentary Service Commission (PSC) meeting, and he would take advice there.
He said he hoped a solution could be found between MPs, rather than turning to the taxpayer for more money.
New Zealand First leader Winston Peters offered to contribute funding from his parliamentary leaders' budget for Ms Mathers to take part in Parliament, and he has challenged other leaders to do the same.
"It is unthinkable that the Parliamentary Service insists on a working environment free from discrimination on the basis of disability, yet a deaf MP is refused funding to enable her to do her job,'' Mr Peters said.
Speaking to media earlier, Ms Mathers said Dr Smith was setting a dangerous precedent for how disabled people were treated everywhere.
"The House is currently not accessible for people with hearing impairments, for the whole of the public ... because we don't have captioning of Parliament television they don't have access to the political debate as it happens.''
Ms Mathers said she had questioned Dr Smith about what would happen in the case of an MP in a wheelchair who needed modifications to Parliament, and had been told that such an MP would not have to fund those alterations.
"He was clear that of course [Parliamentary Services] would pay for it because it was a kind of practical issue rather than hours of support,'' she said.
"The cost of modifying the chamber would probably run to a much greater cost that providing note-taking, so I don't really accept that reasoning.''
