Egypt's electoral commission says it will not allow independent groups to monitor Wednesday's presidential election, defying a court ruling.
President Mubarak is widely expected to win the election
The commission said only supervisors, candidates and their representatives would be allowed in polling stations.
The decision has fuelled fears of vote rigging in the country's first multi-candidate presidential poll.
Campaigning ends on Sunday, with incumbent President Hosni Mubarak widely expected to win.
Mr Mubarak, who has been in power for 24 years, is running for another six-year term against eight other candidates.
On Saturday, the Egyptian judiciary overruled a ban by the government-appointed commission prohibiting local non-governmental organisations (NGOs) from monitoring the poll.
But the electoral commission chief, Osama Attawiyah, told the BBC that the ban would remain in force.
He also said the commission would consider invalid a court decision to exclude one of the presidential candidates.
International monitors are not being allowed to observe the elections either, giving rise to fears the election process will not be transparent.
President Mubarak, meanwhile, is due to round off his campaign with a huge rally in Cairo on Sunday.
The BBC's Arab affairs analyst Magdi Abdelhadi in Cairo says although most Egyptians believe this is an election with a foregone conclusion, 18 days of campaigning have created a lively debate about the country's many social and economic ills.
As a result, for the first time in many years, public attention has focused on domestic problems instead of the usual geo-political conflicts, such as the Arab-Israeli disputes or the violence in Iraq, our analyst says.
He says unemployment, corruption and poor public services are among the many issues that Mr Mubarak has had to defend his record on.
Mr Mubarak's well-choreographed campaign emphasised his experience and the stability he has brought to Egypt in a turbulent region.
His rivals promised a more radical constitutional reform than the one under which Egypt is having its first contested presidential election.