Transport Minister Simon Bridges has defended the process used to pick a Spanish company as preferred bidder for the Warkworth to Puhoi motorway after Northland MP Winston Peters said the company had been hit by corruption allegations.

The New Zealand Transport Agency (NZTA) announced this week that it would enter into preferred bidder negotiations with the Northern Express Group for the Puhoi to Warkworth project - the second Public Private Partnership (PPP) for a state highway project in New Zealand. One of the firms in the group is Acciona Concesiones S.L., from Spain.

Mr Peters, the NZ First leader, said Acciona is tainted by allegations of corruption in Europe.

"So who on earth is doing the due diligence in National, given Acciona executives were arrested in Spain this year for corruption. Meanwhile, the toll roads it has helped to build in Spain have gone bust?"


But Mr Bridges said Mr Peters was just trying to smear the company.

"This attempt at a smear by Winston is pretty sad.

"NZTA has run an incredibly robust process that I have complete confidence in."