FILE PHOTO - Norway's Prime Minister Erna Solberg attends the One Planet Summit at the Seine Musicale center in Boulogne-Billancourt, near Paris, France, December 12, 2017. REUTERS/Benoit Tessier

OSLO (Reuters) - A decision on whether to include the centrist Liberal Party in Norway’s coalition will be made by Monday, two sources said, adding that talks between it and the minority government were advancing faster than planned.

Prime Minister Erna Solberg’s administration consists of her Conservative Party and the smaller right-wing Progress Party. It has been negotiating to bring in the Liberals since the start of January.

Adding the Liberals would make day-to-day governing easier for Solberg, but the three parties together would still hold only 80 seats in Norway’s 169-seat assembly and need support from the Christian Democrats to pass legislation.

Public broadcaster NRK said an agreement had already been reached, but the two sources with knowledge of the negotiations told Reuters on Friday that there was still work to be done.

A deadline of Jan. 19 had been set for the talks, but they were progressing faster than planned, the sources said.

While the Christian Democrats, who hold eight seats, back the prime minister on fiscal matters, they have rejected overtures to enter government.