The Mail & Guardian newspaper has criticised the presidency for releasing a statement on an exclusive story set to appear on its front page on Friday.

"By effectively breaking our story in advance, and robbing us of exclusivity, the presidency has damaged the relationship of trust that we had developed with officials there," said M&G editor-in-chief Nic Dawes in a statement.

The presidency issued a statement on Thursday, saying President Jacob Zuma was not using taxpayer's money to foot the bill for an expansion to his Nkandla homestead.

The M&G said this followed an attempt to obtain comment from the presidency about the construction, giving it a fair chance to respond.

The statement was issued late on Thursday afternoon, just before the paper's deadline.

The M&G said it was a "clear attempt to limit the impact" of the story.

The paper discovered the construction work during a visit to Nkandla at the weekend and had established details of large new houses, a clinic and helipad being built.

It approached both the presidency and the Public Works Department for comment. The former refused to respond and the latter "untruthfully insisted" that no building was underway.

"Competition is an important part of a vibrant media landscape, and the drive to secure scoops is an important energising factor in our constitutionally prescribed work. Skilled communicators understand this, and realise that they need to be able to work with us.

"If government communicators make it impossible for us to trust them with basic courtesy, we will struggle to share information with them, and two things will suffer: their ability to shape our opinions, and the willingness of journalists to seek all sides of every story. Ultimately, that is bad for democracy," Dawes said.

The presidency, in its statement, said the renovations which government was paying for was in line with the security and medical requirements afforded to Heads of State.

These alterations were taking place outside the perimeter of the Zuma household, said spokesperson Vincent Magwenya.

Construction of accommodation for Zuma's security staff, a helipad and a clinic would be paid for by the government.

"The Presidency is fully aware of the need to separate public from private expenditure.

"The demarcation at Nkandla is very clear, and there can be no reason to confuse the private construction work in the Zuma household and the State facilities that will be constructed outside the perimeter."

The Zuma family and not the taxpayer was footing the bill for the expansion of the residence.

"We urge the media to leave the family alone to conduct its business, and reject any insinuation that there could be any untoward abuse of state resources by the president or his family," he said, adding that plans to expand were made before the elections.

"No government funding will be utilised for the construction work. This is a private matter which should be left to the family," Magwenya said.