Spain on Tuesday began to pull the police reinforcements it had sent to Catalonia ahead of a contested independence referendum in the region on October 1, the government said.

Officers from Spain's National Police and Guardia Civil forces sent to the northeastern region at the end of September "will be gradually withdrawn until Saturday", a spokesman for the interior ministry said, adding the withdrawal had started Tuesday.

Shocking scenes of riot police using batons and rubber bullets to remove people from polling stations on the day of the referendum that was banned by the courts made headlines around the world and fuelled tensions in Catalonia.

At leasts 92 people were injured on the day of the referendum, according to hospitals.

Catalonia's separatist authorities said at the time that nearly 900 people required medical attention. The central government's representative in Catalonia, Enric Millo, apologised the following week.

Catalonia has its own police force, the Mossos d'Esquadra, and the other forces usually have a more marginal role in the region. Catalan separatists have dubbed the police reinforcements from other parts of Spain as an "occupying force".

The region has been under direct rule from Madrid since October 27 when the regional parliament declared independence.

Spain's central government also dismissed the Catalan government, dissolved its parliament and called an early election in the region on December 21.

Separatist parties once again won an absolute majority in parliament in that election and are expected to try to form a new government.