CAIRO, April 10 (Reuters) - Egypt blocked a petition website set up to collect signatures against an upcoming constitutional referendum hours after the platform was launched on Tuesday, an internet monitor said.

The proposed amendments to the constitution would allow President Abdel Fattah al-Sisi to stay in power until 2034, bolster the role of the military and increase the president’s power over the judiciary.

Sisi’s supporters say the changes are needed to give him more time to complete major development projects and economic reforms. His critics say they concentrate more powers in the hands of a leader accused by rights groups of presiding over a relentless crackdown on freedoms.

NetBlocks, an internet monitoring group, said the opposition campaign website was blocked after it reached 60,000 signatures on Tuesday. Users were still able to access the website, voiceonline.net, from abroad and or via a virtual private network (VPN) that allows them to skirt local controls.

NetBlocks said network data indicated that access to the site was being restricted by all of Egypt’s internet service providers except for one.

The Ministry of Communications and Information Technology and the Egypt State Information Service could not immediately be reached for comment.

In May 2017, Egypt blocked 21 websites that it accused of supporting terrorism. Middle East and North Africa programme coordinator for the Committee to Protect Journalists (CPJ) Sherif Mansour said that more than 100 news sites are now blocked in Egypt.

Last August, Egypt passed new regulations that allow the top media regulator to block websites and social media accounts with more than 5,000 followers if they are deemed to be spreading fake news or promoting violence, hatred or discrimination.

“This is all part of a new trend ... where the government is shoring up its technical capacity and control on information,” the CPJ’s Mansour said.

The date for the constitutional referendum has still not been confirmed, but Cairo is full of banners encouraging voters to participate. It is expected to take place shortly after parliament holds a final vote on the amendments next week.

An overwhelming majority in parliament, which is dominated by Sisi supporters, voted for the changes in principle in February, with 485 of 596 lawmakers voting in favour. (Reporting by Lena Masri Editing by Nick Tattersall)