Business activity in the euro zone has accelerated much faster than thought this month, in a sign the European Central Bank's bond buying programme may already be paying dividends.

Any indication of a pickup will cheer ECB policymakers, but the surveys also showed firms are still cutting prices to drum up business.

"There is some impetus from quantitative easing, although it is coming at a time when there was already growth, while domestic consumers have benefited from lower prices," said Chris Williamson, chief economist at survey compiler Markit.

As part of its battle to revive consumer prices, which fell 0.3% in February, and to spur growth, the ECB is flooding markets with cash.

The roughly €1 trillion plan appears to be having an impact.

Markit's Euro zone Composite Flash Purchasing Managers' Index, based on surveys of thousands of companies and seen as a good growth indicator, jumped to a near four-year high of 54.1 from February's 53.3.

That beat the highest prediction in a Reuters poll - well above the median forecast for a modest rise to 53.6 - and was its 21st month above the 50 level that separates growth from contraction.

Markit said the surveys pointed to first-quarter growth of 0.3%, matching the previous three months.

However, although a sub-index measuring prices charged rose to an eight-month high of 49 from 47.9, it has now spent three years below the breakeven level, suggesting inflation will not be making any sudden leaps.

Ongoing discounting helped push the PMI covering the bloc's dominant service industry to a 46-month high of 54.3 from 53.7, beating expectations for 53.9. A factory PMI made a similar jump, rising to a 10-month high of 51.9 from 51. The forecast was 51.5.

An index measuring factory output, which feeds into the composite PMI, leapt to a 10-month high of 53.5 from 52.1.

Both headline PMI numbers were driven by new orders flooding in, particularly for services firms where the sub index leapt to 54.6, its highest reading since mid-2011.

Euro zone manufacturing firms were also able to build up a backlog of work for the first time in nearly a year, suggesting the coming months should also be busy.

"All the indicators are pointing to a further upturn, firms are taking on staff and it augurs well for the year ahead," Williamson said.