A pair of Trumps — The Donald and his son Donald Jr. — have hit a new stone wall in Scotland trying to expand their $1.6 billion golf resort project there.

The father-son developers are making little headway trying to buy out five holdout landowners whose homes along a 1,400-acre coastal dune near Aberdeen stand in the way of the resort’s initial groundbreaking in two months.

One key landowner, whose four-bedroom home is a former coast guard station, said yesterday he has already rejected two Trump offers the first for about $286,000 three years ago and a sweetened $376,000 offer in recent days.

“The offer is of no interest to us, as our home is still not for sale,” homeowner David Milne told Bloomberg.

Donald Trump Jr., who’s working as a vice president with his father’s project, said none of the landowners is willing yet to accept sweetened offers equal to about a 15 percent premium to their homes’ recorded market values.

“We are continuing the conversations,” Donald Jr. said, adding it might take another six months of talks. “Some have gone better than others. We can delay temporarily, but it can’t be indefinitely.”

The Trump project — in the planning for several years — four weeks ago won local approval to expand its footprint into the five additional plots of land that weren’t included in the originally approved proposal.

The project includes two golf courses, a 450-room hotel, 500 homes and 950 rental apartments on the Menie Estate north of Aberdeen.

The added five plots are needed for certain logistics in the construction of the resort and golf courses, slated to be completed in about two years.

Trump had planned to start building the first golf course by Nov. 1.

He can apply to local officials for a compulsory sale of the property, a version of eminent domain, unless the local municipal council votes later this week on a proposal to ban such practices for commercial properties.

The project caused a furor nearly two years ago when the Scottish government intervened after the local Aberdeenshire Council rejected the original application. paul.tharp@nypost.com