A majority of Swiss diluting labour rules that protect Europe's highest wages from cross-border competition, a survey published on Friday showed, lending ammunition to sceptics of a new treaty with the European Union. Brussels has put pressure on Switzerland to ease the labour rules under a new treaty that remains unsigned after four years of negotiations. The Swiss government is consulting with domestic power brokers on how to proceed.

A treaty would have the Swiss routinely adopt single-market rules and give EU citizens the same benefits they get when they live in EU countries. Opposition from the anti-EU right and a normally pro-Europe left concerned about sacrificing Swiss sovereignty have left the outcome in doubt. The poll of more than 22,000 people by the Tamedia newsgroup showed 54 per cent of respondents were not ready to make any concessions to the EU on labour rules, which govern EU workers who cross the border on short-term assignments.

Only 32 per cent were ready to change the rules. Fourteen per cent had no opinion. The Swiss government in December opened domestic consultations on the pact, ignoring an EU ultimatum to sign off or face punishment.

Swiss officials said that much of the draft - demanded by Brussels for a decade - was in Swiss interests, but the Swiss side would not endorse the pact for now given differences that remained. The talks are complicated by Britain's negotiations on its departure from the EU, with the Commission reluctant to be soft on the Swiss for fear of providing ammunition to Brexiteers. Some Swiss also want to see what Britain can negotiate for itself before striking their own EU deal.

Swiss-EU ties suffered in 1992 when Swiss voters narrowly rejected joining the European Economic Area. That led to a patchwork of 120 bilateral accords that now govern relations. The treaty would sit atop those accords and focus on five areas: free movement of people, aviation, land transport, mutual recognition of industrial standards and processed farm goods.

If talks fail, the separate accords would stay in effect but relations would suffer badly. No deal would mean no increase in Swiss access to the single market, dashing hopes for a new electricity union. It could also endanger unrestricted EU market access for Swiss makers of products such as medical devices.