The remarks came amid fears that euro zone members Spain and Portugal could soon follow Ireland in requesting help from the fund, which was set up in May by European countries and the International Monetary Fund following Greece's bailout.
Weber, speaking in Paris on Wednesday evening, said Europe would not allow speculators to undermine the euro.
"If that amount is not enough, we could increase it," Weber said. "An attack on the euro has no chance of succeeding."
The fund, to which European countries are contributing €500 billion and the IMF the other €250 billion, aimed to calm fears among investors about the reliability of struggling euro zone members. Ireland's request to tap the fund has, however, underscored the possibility of other countries being forced to seek emergency loans.
On Thursday, the head of the fund, Germany's Klaus Regling, insisted there would be enough money and that there was no way the current debt crisis could sink the euro.
“The safety umbrella would be big enough for everyone," he told daily Bild.
Asked whether there was a danger of the eurozone collapsing, Regling said: “The risk is zero.”
“It is unimaginable that the euro could fail. No country would leave the euro of their own free will - for weak countries, it would be economic suicide and for the strong countries too.”
However he acknowledge that “there is some uncertainty as to whether the crisis could spread to other countries.”
On Wednesday, Ireland unveiled a €15-billion austerity package required to unlock an international bailout reportedly worth €85 billion, slashing public sector pay and pensions but refusing to raise corporate tax.
Regling said he "in no way" believed the crisis could spread to European heavyweights Italy and France.