Weidmann, who sits on the ECB's rate-setting Governing Council, also said that the bank should not make any further changes to the key parameters of its bond purchase scheme, comments that signal opposition to an extension of asset buys since the ECB will soon hit its German bond purchase limits.
Hoping to revive growth and inflation, the ECB is buying 2.3 trillion euros worth of bonds, mostly government debt, a scheme known as quantitative easing and long opposed by Germany, Europe's biggest economy.
The purchases are set to run until December and the ECB will decide this fall whether to extend it in order to boost inflation further or to wind it down, or taper.
"As far as a possible extension of the bonds-buying programme goes, this hasn't yet been discussed in the ECB Council," Weidmann told the newspaper in an interview.
"But in my view, if the solid economic development and price development continues, as expected, it would be time to take a look at an exit from the very easy monetary policies," he said.
Having flirted with deflation for years, price growth is now firmly above 1 percent but will miss the ECB's target of almost 2 percent for years to come, its staff projections show.
A key issue is that self-imposed rules allow the ECB to hold up to one third of each country's debt and given Germany's relatively low debt burden, it is likely to hit this level in the first half of next year.
Any meaningful extension would therefore require a change in the programme's rules, a move Weidmann said he firmly opposed.
A key risk to curbing stimulus may be pressure from governments since any rise in borrowing costs threatens to blow a hole in national budgets after years of rock-bottom borrowing costs.
"This can lead to a political pressure on the Governing Council to continue the loose monetary policies longer than necessary," Weidmann said.
Weidmann, touted a potential successor to ECB President Mario Draghi when his term ends in late 2019, also said that Germany was not in need of stimulus as employment and capacity utilisation were already high.
(Reporting by Balazs Koranyi; Additional reporting by Erik Kirschbaum in Berlin; Editing by Ros Russell)