Strutt and Parker said the number of estates changing hands had fallen in 2013, with the overall value of such properties dropping by almost half compared with previous years.
Partner Robert McCulloch said that over the last five years an average of 17 estates had been sold in Scotland each year, at a combined price of £63 million annually. By the end of November this year, however, just seven estates worth a total of £35m had been sold.
Mr McCulloch, who specialises in buying and selling farms and estates, said the "easy and obvious" factor was the uncertainty caused by the referendum.
He said: "We have a number of people from the UK and abroad, who are very aware of the referendum debate, but they are still keen to buy an estate in Scotland.
"But prospective vendors who don't have to sell their property, appear to think they should see how it plays out and take the plunge thereafter.
"They seem to think the uncertainty created by the referendum will negatively impact on the price they could achieve, so they hesitate."
Mr McCulloch said that despite the fall in sales, his team had its busiest and most productive year since the start of the recession in 2008 and the market in farms remained very strong.
His company had offered for sale 18 farms situated in 11 different counties with a combined asking price of more than £28.8 million. As the year ends, 15 of these had been sold or were under offer at a combined total price of just in excess of £28m.
He said: "This market has been strong because the buyers are generally existing farmers from within the UK. They are often well funded and the banks are prepared to lend to them."
Mr McCulloch said there had been very few Highland sporting estates for sale this year which were offering top quality deer stalking and no driven grouse moors.
"Yet this type of property remains in strong demand," he said.
He added, however, the company had sold several important estates. North Dryburgh Estate in the Borders, which offered salmon fishing on the River Tweed, was on the market at offers over £3.5m and achieved in excess of that.
Mayen Estate in Aberdeenshire, which includes a house, fishing on the River Deveron, farming and sporting interests, was sold for over the £4m asking price.
Meanwhile, there is serious interest in Balavil Estate near Kingussie which extends to about 7500 acres running from the River Spey up into the Monadhliath Mountains.
It is on the market at around £7m, offering a combination of farming, red deer and roe deer stalking, driven grouse and pheasant shooting, salmon fishing and commercial forestry.
"There has been a number of viewings by prospective purchasers from within and outside the UK," Mr McCulloch said.
Balavil has a colourful past, imagined and real. It featured in the TV series Monarch of the Glen, as the home of Lord Kilwillie, as played by Julian Fellowes, later the creator of Downton Abbey.
The house was built by the sometime 18th century colonial administrator and MP for a constituency in Cornwall, James Macpherson.
He gained fame and notoriety in the 1760s for the literary sensation of apparently finding and translating ancient Gaelic works of Ossian, the legendary Celtic warrior and bard.
In fact much of it was his creation.
The Gaelic-speaking Macpherson had been born in the area and died in Balavil, but was buried in Westminster Abbey.