South African president Jacob Zuma will visit Zimbabwe Tuesday to try and break the deadlock on the political agreement which led to the formation of the inclusive government more than a year ago.

Mr. Zuma is due to arrive in Harare on Tuesday amid growing signs of stalemate in the 13-month-old unity government.

And just a day before his arrival, Zimbabwe's Prime Minister Morgan Tsvangirai is already weighing in. He says the unity government has failed to institute significant democratic reforms and accuses his old rival, President Robert Mugabe, of blocking them.

ZANU-PF has said it will not make any more concessions to MDC claiming it has fulfilled everything expected of it under the power sharing agreement.

Mr. Tsvangirai has appealed for President Zuma to intervene in his key role within the regional body of Southern African Development Community (SADC), which has guaranteed the political agreement. But, the prime minister has a tough road ahead.

In recent weeks, Mr. Mugabe has stripped several MDC ministers of their power and given them to his own ZANU-PF allies. One of the ministries controls elections, and is headed by the Justice Minister Patrick Chinamasa. Calls to Chinamasa were not returned.

The MDC says it wants to persuade Mr. Zuma that the only solution to the deadlock is fresh elections. Mr. Mugabe has also called for new elections.

Apart from stripping the MDC ministers of their jobs two weeks ago, the MDC says it will tell Mr. Zuma that its main concern remains the appointment of the pro ZANU-PF attorney-general, Johannes Tomana who they accuse of selective prosecutions focusing on the MDC.  The MDC also says the appointment of Tomana was unilateral and, therefore, in violation of the political agreement.

Mr. Mugabe says the main obstacle to progress in the unity government is U.S. and European Union travel and financial restrictions against the hierarchy of ZANU-PF and some of their companies.

During his recent state visit to Britain, Mr. Zuma called on Prime Minister Gordon Brown to lift the targeted sanctions against Zimbabwe.

Mr. Zuma will be in Harare for two days. His team on Zimbabwe, which is headed by political adviser Charles Nqakula, has been working with the parties in Zimbabwe since December 2009.  The MDC narrowly won the 2008 elections and Mr. Tsvangirai won more votes than Mr. Mugabe in the first round of the presidential poll but withdrew from the run off after about 200 of his supporters were killed and thousands injured.