Madrid  - Spanish haulage companies launched an indefinite strike Monday, sparking fears of shortages at markets, stores and petrol stations, media reported.

Some lorry drivers had staged protests already last week against fuel prices which have risen 36 per cent over the past five months.

Lorries blocked roads, prompting long queues especially at the French border.

The protests were described as the most serious social conflict faced by Socialist Jose Luis Rodriguez Zapatero since he became prime minister in 2004.

The hauliers want the government to cut fuel-related taxes and to establish a minimum price for transport services, demands that the government has rejected.

The government is proposing a package of alternative measures such as more flexible contracts and financial facilities to older drivers willing to retire.

Fishermen and farmers are also staging protests against the fuel prices.

People fearing shortages queued at petrol stations and supermarkets over the week-end. Less lorries were arriving at markets, but no significant shortages have yet been observed, reports said. (dpa)