Turkey's government faced growing pressure Thursday to quickly implement a top court order to unblock Twitter, which it had banned after corruption claims went viral on the social media site.

Prime Minister Recep Tayyip Erdogan ordered the block on March 20 in the lead-up to last Sunday's key local elections, in which his party won sweeping wins despite the damaging online leaks.

On Wednesday Turkey's Constitutional Court ruled that the Twitter ban breached free speech, and ordered the communications ministry and telecoms authority to reverse it "with immediate effect".

The US-based micro-blogging service reacted quickly to the ruling, tweeting: "We welcome this Constitutional Court ruling and hope to have Twitter access restored in Turkey soon."

But although the ruling by the country's highest court was published Thursday morning in Turkey's Official Gazette, by mid-morning the service still remained unavailable in Turkey.

Sezgin Tanrikulu, a lawmaker for the secular main opposition Republican People's Party, said he would lodge a complaint unless the government abides by the court ruling, warning that defying it "would mean an abuse of power".

Tanrikulu -- who was among the group that had lodged the initial challenge with the Constitutional Court -- warned that the ruling is "binding for everyone, including Prime Minister Recep Tayyip Erdogan, who does not recognise the law".

President Abdullah Gul, a regular Twitter user, also said the bans on the micro-blogging service as well as on video-sharing service YouTube should be reversed.

"The bans on Twitter and YouTube now need to be lifted. I've expressed this to the minister and to the authorities," Gul was quoted as saying by Hurriyet newspaper on Thursday, while on a visit to Kuwait.

'We will evaluate verdict'

A US State Department spokeswoman had told a regular Washington media briefing: "If there has been a court decision, we think it needs to be implemented quickly, as quickly as possible".

EU Enlargement Commissioner Stefan Fule tweeted: "Good news for freedom of expression in Turkey: Constitutional Court orders lifting of Twitter ban. Looking forward to swift enforcement!"

But a lawmaker from Erdogan's ruling Justice and Development Party (AKP) suggested Thursday that the court ruling may not be implemented immediately.

"It is only about individual complaints to the Constitutional Court," Mustafa Sentop told CNN-Turk television, suggesting that the ban may only be lifted for the three individuals who had launched the court complaint.

"We will evaluate the verdict."

Telecoms regulator TIB declined to comment when contacted by AFP.

Since December, Twitter had been used to anonymously release a spate of audio recordings that purported to expose corruption involving Erdogan's relatives and allies.

The ban has been widely circumvented by Twitter users, who have instead sent tweets via text message or by adjusting their Internet settings.

Polling has shown that the Twitter and YouTube bans, despite widespread condemnation from NATO allies and human rights groups, had little effect on Erdogan loyalists at Sunday's elections.

Research centre Ipsos found that only 3.6 percent of AKP supporters said they had been affected by the Internet blocks, and three quarters said the corruption claims had "no effect".

Millions of Turks approve of Erdogan, despite criticism of a growing authoritarianism, because of the strong economic growth seen during his 11-year rule, analysts say.

"The Turkish economy is betting on Erdogan as an anchor of stability, and so are the people," said Michael Meier of German think-tank the Friedrich-Ebert-Foundation.

"The corruption allegations are there, but at times of economic growth voters are pragmatic. That's because there's still enough left of the cake to go around."

Meier added that "Erdogan has been able to touch the Turkish soul and pride ... To many he embodies the dream of rising from a poor Istanbul neighbourhood to head of government."