Google shifted the blame for widespread unavailability of its search services in China on Tuesday to the authorities in the country, after earlier in the day saying that a technical flaw in its own systems had caused the problem.

The confusion came as many Chinese internet users found themselves unable to reach Google’s services for the first time since it took steps last week to evade Chinese ­censorship of politically sensitive searches. Google, along with many observers, has feared a backlash from ­Beijing.

The problems began in the evening in China when searches for words as harmless as “dog” or “home” turned up a browser error. Google later said its users had experienced widespread disruption for several hours, before full service was resumed.

At first, the US internet company took the blame, saying that it had configured its servers by accident in a way that made all its traffic appear to involve an organisation banned by the Chinese government. This had led to an automatic blocking of its search results by China’s “Great Firewall”, which filters information coming into the mainland, it said.

However, several hours later Google said the problem “must have been as a result of a change in the Great Firewall”, since it had discovered that the technical change to its own systems took place a week ago and so could not have caused yesterday’s problems. It added that full ­service had been resumed, though not as a result of any changes to its own ­systems.

Action by authorities would raise the threat that Google could lose most of its revenue in the market with the world’s largest internet population.

The search problems appeared to mark a sharp escalation of issues users had experienced over the past week. Similar errors have been reported on a number of occasions, though none lasted more than an hour at a time.

Google had originally said that a string of characters it had introduced to all its search queries globally to improve results included the letters rfa, which happen to stand for Radio Free Asia. “Because this parameter contained the letters rfa the great firewall was associating these searches with Radio Free Asia, a service that has been inaccessible in China for a long time – hence the blockage,” Google said.

Calls for comment to the ministry of industry and information technology and the state council information office went unanswered last night.