The American billionaire property developer, Donald Trump, has ridden roughshod over a  warning from his own scientific adviser that his controversial plans for a golf complex in Aberdeenshire could ruin the environment.

Dr Tom Dargie, a paid scientific consultant to Trump International Golf Links Scotland, told his employers the proposed golf course would pose "a very significant threat" to the unique system of sand dunes at the Menie Estate, near Balmedie. But Dargie's advice to move the links inland to avoid causing serious damage was ignored by the Trump organisation, which insisted it needed to develop the dunes in order to create a "world-class" golf resort.

A fiercely contested public inquiry into Trump's plans is due to open in Aberdeen's Exhibition and Conference Centre on Tuesday morning.

Trump is expected to visit his mother's birthplace on the Isle of Lewis tomorrow, and then to give evidence to the inquiry the following day. In a formal submission to the inquiry on behalf of the Trump organisation, Dargie has outlined his criticisms of the development.

Dargie had expressed concern about the plan's impact on the Menie dunes to the government's conservation body, Scottish Natural Heritage (SNH), in 2006. As one of the UK's top experts on the ecology of coastal dunes, Dargie stressed that every attempt should be made to keep them as they were.

"I also suggested this coastal stretch is probably the most dynamic set of dunes in Britain and that golf development was a very significant threat to site geomorphological and ecological integrity," he said.

Dargie was then approached by the Trump organisation in May 2006 and asked to survey the area's plant life, some of which is legally protected as a Site of Special Scientific Interest (SSSI).

"I made my views on the development clear to the team and the applicant," he said. "I asked the applicant to move the course inland, away from the SSSI and other dunes. It was explained that earlier work had considered but rejected this. The applicant required the dune ground due to its outstanding potential for a golf course."

Dargie has surveyed - for SNH and others - most of the major dune systems in Scotland and many others in the UK. Formerly based at Dundee and Aberdeen universities, he now runs a Dornoch-based consultancy, Boreas Ecology.

He will be one of Trump's main witnesses at the public inquiry, and is expected to appear on June 16-17. He is due to give evidence on the possibilities of mitigating the environmental impact of the golf course, but is likely to face questions over his concerns about the siting of the development.

Dargie was reluctant to say much in advance of the inquiry. "I'm an adviser, I can only advise. Ministers decide, developers decide," he said. "The Trump organisation has the right to ignore the advice of its environmental scientists."

But opponents of Trump's plans seized on Dargie's remarks. "Donald Trump faces a huge challenge in trying to persuade the inquiry that he has a credible development plan for his proposed golf course," said Dave Morris, director of Ramblers' Association Scotland. "The Trump organisation's dismissive and contemptuous attitude towards anyone who opposes his plans suggests we will see some robust exchanges in this week's inquiry."

Morris pointed out that an eminent golf course designer had also sounded warnings over the development. David McLay Kidd, of DMK Golf Design, said Trump would "have to tread very lightly" to avoid damaging the dunes.

According to the Green MSP, Patrick Harvie, it was "astonishing" that Trump had overruled his own environmental adviser. He added: "If even The Donald's hired hands can see how unacceptable the plan is, we're confident that the public inquiry will see sense and either block the application altogether or at least move it back off the dunes."

One of the main objectors at the inquiry will be the Royal Society for the Protection of Birds (RSPB). "It is encouraging that others acknowledge the environmental impact of this development as proposed," said RSPB Scotland's Lloyd Austin.

However, George Sorial, who is managing the links project for Trump, defended the plans. "It is unfair to suggest we are destroying a coastal dune system," he said. "Almost 90% of the site will be left untouched."

He accepted that every development involved some "environmental sacrifice". But the economic and other benefits of the golf resort would make that sacrifice worthwhile on the Menie Estate.

"Could we design a course that avoids the SSSI? Of course we could. But it wouldn't enable us to do something truly world-class," Sorial argued.

The Trump organisation would be doing its utmost to minimise and mitigate any impact on the dunes, he stressed. That was why it had hired leading experts such as Dargie to ensure it had the best possible advice.

"Tom is a scientist and has his own integrity to preserve," Sorial said. "We should be commended for our frankness and forthrightness about this scheme."