Turkey's parliament is deadlocked over efforts to draw up a new constitution aimed at enshrining democratic values and replace a military-drafted charter, a ruling party lawmaker said Wednesday.

A special cross-party parliamentary commission set up to write a replacement for the charter introduced by the military junta after a 1980 coup is set to be formally dissolved after failing to make any significant progress.

"The parliamentary commission tasked with writing a new constitution could not produce any article over the last four months," Ahmet Iyimaya of the Justice and Development Party (AKP) told AFP.

He said it was unlikely a new constitution -- a key pledge of Prime Minister Recep Tayyip Erdogan's latest term in office -- would be ready before a general election in 2015.

One of the major disputes over the constitution lies with plans by Erdogan's AKP to introduce an executive presidential system in the predominantly Muslim but staunchly secular state.

Observers say Erdogan -- who has been prime minister for 11 years -- is hoping to change the constitution to give the president US-style executive powers before running for the post himself next year.

The current presidency, held by Abdullah Gul since 2007, is largely a symbolic post.

Political parties in the 550-seat parliament have been working since 2011 to replace the current constitution which was drafted by the powerful military after the 1980 coup.

But little progress has been made.

"It looks difficult to write a new constitution before the general elections," Iyimaya said.

The commission has succeeded in reaching a compromise on 62 articles but discord remains on numerous articles including citizenship and language rights.

The government had aimed to draw up the new charter before three major elections: local polls in March 2014, followed a few months later by a presidential ballot and then a general election in 2015.

"It's hard to write a new charter in an election atmosphere," Iyimaya said.

Parliament speaker Cemil Cicek said on Monday that he planned to withdraw from the commission, a move that could effectively lead to its abolition.

"The commission has collapsed after the withdrawal of its head," said Iyimaya.