Corrects after stats office said GDP gain was biggest since reunification instead of biggest gain in 23 years.

German gross domestic product grew 2.2 percent in the second quarter, the biggest gain since reunification, driven by investment and exports, the Federal Statistics Office said on Friday.

The preliminary quarter-on-quarter reading was well above the Reuters consensus forecast for a 1.3-percent expansion.

First-quarter growth was revised up to show growth of 0.5 percent, after being previously reported at 0.2 percent.

Year-on-year, the economy grew by 4.1 percent in the second quarter, the data showed. This followed a revised 2.1 percent expansion in the January-March period and beat expectations for 2.4 percent growth year on year.

(Reporting by Paul Carrel and Annika Breidthardt)