The chief economist of Germany's biggest bank says he expects Portugal to seek a bailout from other eurozone countries soon as the sovereign debt crisis continues to erode market trust.

German Sunday newspaper Frankfurter Allgemeine Sonntagszeitung quoted Deutsche Bank AG's Thomas Mayer as saying he "wouldn't be surprised if Portugal would in the near future seek help in addition to Greece and Ireland."

The newspaper further quoted Mayer as saying the government in Lisbon would be "well-advised to move swiftly" under the protection of Europe's 750 billion euro ($980 billion) rescue fund.

Mayer also told the newspaper that Spain, Italy and Belgium enjoyed much better fundamentals and would not need outside help to refinance their deficits.