A New South Wales' man has lost his fight against fast-food giant McDonalds to register the trademark 'McKosher'.

McDonald's, which has 35,000 restaurants around the world, has been to court several times to protect its Mc prefix, with its latest challenge taking place in Maclean, on the NSW north coast.

The Australian Trademark Office was told the town's residents pride themselves on the fact Maclean is the Scottish capital of Australia.

A hearing into the matter was told that for many years the people of Maclean township have publicly used the Mc and Mac prefix to describe and market many activities including McMarkets, MacMarkets, MacBowlo, MacConsultants and MiniMacMarkets.

The trademark applicant, Mark Glaser, told the office hearing he was of Scottish Jewish descent and his ancestors' surnames included McKosher, MacAdoo, Beadle, Zimmerman, Rosenthal and Glaser.

He said he hoped to open a Scottish and Jewish restaurant bearing the name McKosher.

But the fast-food giant noted calls by a group of powerful rabbis in Jerusalem for the chain to rebrand kosher-friendly restaurants there as McKosher.

The Australian Trademark Office was told: "Rabbinical leaders are in negotiations with the international fast-food chain, McDonald's, over the issue of the name of the chain in the capital."

"The Jerusalem Rabbinate refuses to certify any of the chain outlets in the capital as kosher so long as there are any non-kosher branches in the city," McDonald's lawyers said.

"The certifying rabbis fear that a kosher certificate in one branch will mislead the public into assuming that all of the local McDonald's outlets are kosher.

"The solution suggested by the Rabbinate is a renaming of the kosher McDonald's branches to 'McKosher'.

McDonald's lawyers said corporate representatives in Israel had told the rabbis such a drastic change would require the approval of the chain's international headquarters.

The office has refused Mr Glaser's application to register the trademark McKosher, noting there was a likelihood of contextual confusion.