Internet provider TPG indicates it is unlikely to improve its $1.4 billion offer to take over rival iiNet, despite unrest among some key shareholders.

The founder of iiNet, Michael Malone, is among those who are calling for the bid to be rejected and for the board members recommending it to be replaced.

Mr Malone founded iiNet in his mother's garage in Perth back in the early 1990s when a lot of people thought the Internet was just a fad.

Last year he stepped away from running the company but still owns 2.5 per cent of the stock.

Mr Malone yesterday said on an iiNet investor conference call that the offer of $8.60 a share from TPG is not good enough, despite saying it sounded like a sensible and good deal last week.

"I believe that this deal is incomplete, unprofessional and reflects poor diligence - it's been ten days since the deal was announced and you now think it's time to talk to shareholders," he told iiNet's current management.

"I don't believe this has been marketed well, I don't believe he's tested the market.

"I think it's bad for shareholders, it's bad for sales, it's bad for our customers, and you haven't even talked about staff and customers on this call, at what point will you actually think about other stakeholders?"

TPG's chief financial officer Steve Banfield told investors on his firm's results briefing teleconference today that the company respects Mr Malone and would be happy to meet with him to discuss his concerns.

"We're disappointed by the reaction of certain shareholders given our genuine belief that we're proposing a great deal for iiNet shareholders. TPG's offered a full and fair value for iiNet," he said.

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Mr Banfield responded to questions from the ABC on the call by saying the company only recently became aware of Mr Malone's concerns.

"Neither our advisors nor anyone at TPG received any communication from Michael Malone until late on Sunday, just 36 hours ago. We'd be very happy to meet with Michael. He's someone we respect greatly," he replied.

In relation to the iiNet bid, TPG made an argument that the $8.60 per share offer is compelling and represents a 33 per cent premium.

TPG is also citing broker reports saying the iiNet share price probably wouldn't hit $8.60 for the next two years, so iiNet investors are being offered fast money and a degree of certainty.

TPG reported a strong half-year profit, up 18 per cent to $106 million.

TPG shares had risen 3 per cent to $9.09 by 3:56pm (AEDT) on the firm's first-half results, while iiNet stock had fallen 2.2 per cent to $8.66.