Leader of the Norway's opposition Labour party Jonas Gahr Stoere poses for a picture in parliament in Oslo, Norway May 30, 2017. REUTERS/Gwladys Fouche

OSLO (Reuters) - Support for Norway’s opposition Labour Party has fallen sharply and the centre-right government has taken the lead ahead of the Sept. 11 election, according to a poll published by public broadcaster NRK on Tuesday.

Labour and its partners hitherto had been ahead in polls to form the next government. In the latest survey, Labour’s support fell to a four-year low of 27.1 percent from 33 percent in a similar poll conducted in June, NRK said.

Those who voted for Labour in the last election four years ago are now unsure, with one in 10 Labour voters back then now considering voting for the current government, NRK said.

With four weeks to go before an election that is too close to call, even small changes in support for some of the nine parties on the left and right could ultimately decide the outcome.

(For a graphic on 'Norway parliamentary elections' click here)