Tauranga detectives are now formally investigating dishonesty allegations made against MP Brendan Horan, but the Tauranga independent says this is nothing new.

'It's nothing new. They did it ages ago and a story ran about it two or three weeks ago and was repeated by Radio New Zealand,” says Brendan today.

Tauranga Independent MP Brendan Horan is looking to form a new political party ahead of this year's general election in November.

The police investigation is a result of a complaint laid by NZ First leader Winston Peters to the Serious Fraud Office in November 2013.

The SFO referred the complaint to Tauranga Police, who then had to assess the complaint before launching an investigation.

Western Bay of Plenty police area commander Inspector Clifford Paxton confirmed today that the assessment of the SFO is complete and it has now moved into an investigation by Tauranga detectives.

'While the investigation is ongoing there will be no further police comment," says a statement from the area commander.

A Radio New Zealand story on June 6 reported the investigation will take about a month.

'It's been with the detectives for quite some time,” says Brendan today.

Brendan's half-brother Mana Ormsby accused Brendan of using their late mother's bank cards in December 2012, and as a consequence NZ First leader Winston Peters expelled Brendan from the party.

Olwen Horan, 87, died on August 3, 2012 with $3000 left in her bank account and her home, which sold for $425,000.

A codicil to her will written a month before she died authorised her nephew John Buckthought to recover monies loaned to her daughter and Mr Horan or taken by "misadventure".

After a private investigation, nephew and executor John Buckthought said he could find no evidence enabling him to find a claim against Brendan. Brendan was paid out his remaining share of the estate.

On Maori Television's Native Affairs last night Brendan told Mihingarangi Forbes that it has been a terrible time to have a close knit family portrayed so poorly and falsely.

'And have people made political gain out of it, is I think really disgusting,” says Brendan.

'The police have a responsibility to take these complaints seriously and so they are doing their job and I'm fine with it.

'I'm not at all concerned, it's old news there's nothing new.”

He confirmed the contents of a NZ Herald story published Saturday stating changes to his mother's will were made by Brendan's brothers, sickness beneficiary Mana and recently discharged bankrupt Peter.

'The NZ Herald one, he actually got it right. He went and spoke to my brother,” says Brendan today.

They discovered shortly before Olwen Horan's death that she had spent all the money from a lottery win they believed they had a claim to.

Changes to the will included a $150,000 payment to Peter Horan, which had not appeared in earlier wills, and the clause that ended Brendan's political career with New Zealand First – seeking an investigation into spending by Brendan and his sister Marilyn Bleackley.

After being expelled from NZ First, the Speaker of the House declared Brendan an independent list MP, and he has remained in Parliament.

Brendan's time as an independent MP opened his eyes to deficiencies in the party political system and he is in the process of launching a new political party, a coalition of independent MPs.

The New Zealand Independent Coalition is in the process of being registered as a political party, and they are seeking candidates from all round the country, says Brendan.

'I'm really quite excited about having the opportunity to change politics for the better in New Zealand, and moving away from party politics and interest groups behind parties to putting the people of our country first.”