CADIZ, Spain, Nov 24 (Reuters) - Striking metalworkers near the southern Spanish city of Cadiz clashed with police on Wednesday after a mass walkout involving tens of thousands of employees entered a second week.

TV footage showed police in riot gear firing pellet guns while demonstrators hurled rocks, including from handheld slingshots, from behind burning rubbish containers.

A local police spokesperson said on Wednesday afternoon that there had been no serious incidents and order had been restored.

The strike began on Nov. 16, after unions and the FEMCA association of 700 local metal-working companies failed to reach a new collective bargaining agreement.

Picketing workers have since cut access to Cadiz's main industrial zone with bonfires and blockades.

Though multinationals in the area like Airbus, ACS subsidiary Dragados Offshore, and shipbuilder Navantia are not involved in the strike, their operations have been disrupted.

An Airbus spokesperson said that since the strike began, workers at the Puerto de Santa Maria had been unable to get past the picket lines, and were only able to enter on Wednesday with police assistance.

Police and unions say the demonstrations have been mostly peaceful but have occasionally turned violent. Two people have been arrested since the strikes began.

Labour relations have long been strained in the historic port town on Spain's Atlantic coast, which suffers from one of the country's highest unemployment rates despite being home to a major industrial hub and several tourist draws.

With inflation running at a near three-decade high, unions want wage increases to be linked to the consumer-price index to ensure workers do not lose purchasing power.

They have sought a 2% pay rise this year, followed by increases of 2.5% in 2022 and 3% in 2023, a proposal that FEMCA described as "unrealistic".

Both sides have traded accusations of inflexibility in subsequent negotiations.

Before heading into the latest round of talks on Wednesday, Antonio Montoro, secretary general of the UGT union in Cadiz, said he would stay at the negotiating table as long as necessary and asked business representatives to act responsibly.

"The situation is getting increasingly tense and... increasingly complicated to reach an agreement," he said. (Additional reporting and writing by Nathan Allen; Editing by Andrei Khalip and Jan Harvey)