Germany may change constitution over economic crisis

Ms Merkel made the comments while unveiling a second stimulus plan worth €49.25 billion, to be spent over two years and made up of public investments and tax cuts.

The constitutional amendment would prevent German governments from raising the state's public deficit above 0.5 per cent of GDP "in normal economic times", the Financial Times reports.

This would have capped 2008 borrowing at €12 billion.

The EU's Stability and Growth Pact, which limits Eurozone budget deficits to three per cent of GDP, was relaxed last year as the economic downturn escalated.

In addition to Germany's proposed constitutional change, the finance ministry is to set up a "redemption fund" to ensure the government pays back the latest stimulus plan by a set date.

The redemption fund could collect revenues from future government windfall taxes once economic growth reached a certain threshold.

A similar fund was set up to pay back borrowing related to German unification.

Both measures highlight German fears over the potential long-term damage to Europe's monetary union caused by excessive public borrowing, concerns shared by Belgium and the Netherlands.

In a sign that investors are increasingly differentiating between Eurozone countries, yield margins between German and other Eurozone bonds have widened considerably in recent weeks.

Yet even Germany failed to sell €6 billion worth of government bonds last week, a sign likely to worry other less prudent governments looking to raise money for spending projects.

Portugal receives credit warning

Separately on Tuesday, Portugal received a warning from credit rating agency Standard & Poor's, the fourth Eurozone state to do so in as many days.

On Monday, Spain was warned by the same agency that its rating was in danger of being downgraded, as were those of Ireland and Greece last Friday.

High ratings are vital to enable cheap borrowing on international money markets and any downgrades could prove costly at a time when national governments are looking to spend considerably more than tax returns allow.