ZURICH (Reuters) - Swiss right-wing leader Christoph Blocher and allies fired a salvo on Friday against negotiations to bind Switzerland more closely to the European Union, saying it would be a strategic error to join forces with such a crisis-ridden entity.

Negotiations are about to wrap up on a "framework treaty" that would put Swiss bilateral ties with its most important trading partner on a more comprehensive basis, and Blocher's Swiss People's Party (SVP), the biggest in parliament, opposes any agreement that goes beyond existing favorable trade terms.

Blocher, head of the Committee Against a Creeping EU Entry, told reporters Switzerland could never agree to a pact that let Brussels impose binding EU rules and regulations on a sovereign nation and then have EU courts rule on any disputes that arose.

"Foreign laws, foreign judges. That is a very fundamental decision we have to make, along the lines of the 1992 decision on entering the European Economic Area and then the EU," he said, referring to Swiss voters' rejection of that process.

Instead, Switzerland has arranged a series of bilateral economic accords that now are jeopardized by a standoff over Swiss demands to limit immigration from the EU. Talks on that issue come to a head in September.

SVP party leader Albert Roesti said it would be "fundamentally false" strategically to bind Switzerland more closely to a union battling debt, financial and refugee crises at a time when Britain had decided to leave the bloc.

The negotiations on forging closer institutional ties are separate but parallel to the immigration talks. Any deal would have to win parliamentary approval and then face a potential referendum under Switzerland's system of direct democracy.

(Reporting by Michael Shields; Editing by Louise Ireland)