The company said yesterday: "Management is willing to consider strategic third-party partnerships, alliances and equity stakes in case such an approach is seen as beneficial for GM Europe and Opel/Vauxhall's viable and sustainable future."
GM's US rival Chrysler is already considering selling a 35% stake to Italy's Fiat in a bid to solve its own financial problems.
GM's admission came as European governments issued a cool reaction to the car manufacturer's request for a $6bn rescue package that would supplement the $16.6bn (£11.7bn) package it is attempting to get from the US government on top of the $17.4bn it has already borrowed.
The GM restructuring plan, which calls for redundancies for 47,000 workers out of its 244,000 global workforce, is very likely to lead to job losses at its European factories and threatens its Sweden-based Saab unit with bankruptcy.
GM's appeal to the Swedish government to help it prop up Saab was criticised yesterday by Swedish industry minister Maud Olofsson, who said she was "deeply disappointed" in GM.
Olofsson said: "They have in practice removed their hands from Saab ... they are handing over responsibility to Swedish taxpayers."
The German and UK governments both called on GM to provide them with clear restructuring plans.
A spokesman for the UK's Department for Business, Enterprise and Regulatory Reform said: "We are continuing to discuss the implications of the plan with the company, although there is no specific detail as yet on how it might affect Europe, and how we can continue to help GM in the UK."
GM is hoping to sell Saab and Hummer to improve its finances and is to sell or discontinue its US brand Saturn by 2011 as well as scale down its Pontiac division.
GM Europe's agency roster includes UK-based DLKW, Lowe and McCann Erickson.