Egypt will hold new parliamentary elections once amendments to its suspended constitution are approved in a referendum, the interim head of state decreed on Monday, setting out a timeframe that could see a legislative vote in about six months.

A presidential vote would be called once the new legislative chamber convenes, the decree said. It set a four-and-a-half month timeframe for amendments to the state's controversial, Islamist-tinged constitution that was passed in December.

That constitution was suspended last week when the army removed elected Islamist President Mohamed Mursi from power following mass protests against his rule.

The decree gave the interim head of state the power to issue laws after consulting with a government expected to be formed soon, and until a new parliament is elected.

It also kept an article that has been in Egypt's constitution for decades and defines the principles of Islamic sharia law - the country's main source of legislation.

In what appeared to be a gesture to Islamic parties, it also included more controversial language put into the constitution last year by Islamists and which defined the principles of sharia. Liberals and Christians had opposed the article as one of several that gave the text an Islamist tone.

Spokesmen for the National Salvation Front liberal coalition and the second biggest Islamist group, the Nour Party - which both agreed to the army-backed transitional roadmap - said they needed time to read the decree and consult their leadership before commenting.