Image copyright Press Eye Image caption Arlene Foster said the National Crime Agency was the appropriate organisation to investigate the matter

First Minister Arlene Foster has rejected a call by Martin McGuinness for a cross-border Nama inquiry saying it was "not appropriate".

Mr McGuinness said he supported such an inquiry following new revelations about Nama's role in Northern Ireland's biggest ever property deal.

The allegations were broadcast by the BBC's Spotlight programme on Tuesday.

However, Mrs Foster said the National Crime Agency was the appropriate organisation to investigate.

The programme reported that ex-Nama adviser Frank Cushnahan was recorded accepting a £40,000 cash payment from a Nama borrower.

Image caption Martin McGuinness, deputy first minister of Northern Ireland, said a cross-border inquiry should begin when criminal investigations have been completed

Mr Cushnahan, who was advising Nama at the time, has denied any wrongdoing.

Mrs Foster said the NCA would continue to investigate and once that process was over they could look forward to any other "consequential investigations" which have to take place.

"We have always been very clear that the NCA is the appropriate and professional organisation to deal with any allegations," she said.

Media playback is unsupported on your device Media caption Frank Cushnahan was recorded accepting payment of £40,000

Nama sold its entire Northern Ireland property loan portfolio to a US investment fund in April 2014.

However, the £1.24bn deal has been embroiled in controversy since July 2015, when allegations of political interference were made in the Dáil (Irish Parliament).

The transaction is now the subject of investigations by US detectives and the UK's National Crime Agency (NCA).

Mr McGuinness, deputy first minister of Northern Ireland, said a cross-border inquiry should begin when criminal investigations have been completed.

"What we need is, obviously, the police investigations - whether it be the American ones or on this side of the water - expedited as quickly as possible so we can have full information about what was actually going on.

"And then I think we need an all-Ireland investigation with the administrations north and south co-operating to, as best they can, get to the bottom of what was happening."

Meanwhile, Ulster Unionist leader Mike Nesbitt has written to the permanent secretary of HM Revenue and Customs to ask whether the agency is going to investigate the allegations contained in the Spotlight programme.

"Given how serious the allegations made during the programme were, they must receive full and robust investigations," Mr Nesbitt said.

Image copyright BBC Newsline Image caption Mr Cushnahan, a former banker, was a Nama adviser from May 2010 to November 2013

The call for an all-island commission of inquiry into Nama was made by the chairman of the Irish Parliament's finance committee.

Speaking to BBC Spotlight, Fianna Fáil's John McGuinness said a "cross-border effort must be made to get to the end of this, to get to the truth".

The payment to Mr Cushnahan was made by the County Down property developer John Miskelly during a meeting in a hospital car park.

Mr Miskelly said "payments made by me to any persons have been lawful".

Mr Cushnahan has denied any wrongdoing and told BBC Spotlight NI he would not be providing any further responses because of the ongoing NCA investigation.