South African contractor Murray & Roberts has made a bid to take over engineering and project services company Clough Ltd, by buying the roughly 40 per cent stake in the group it does not already own.

Clough chairman Keith Spence said the board would support the deal,

subject to conditions, and that M&R did not intend to make any "material changes" to group's operations or management.

M&R, which owns 61.6 per cent of Clough, has made a conditional $1.46 per share cash and dividend offer for the remaining stake in the group.

The offer price is at a 30.9 per cent premium to Clough's closing price yesterday of $1.115.

M&R, a South African engineering, contracting and construction services group, would pay $1.32 in cash per share, while Clough would chip in a fully-franked dividend of $0.14 per share.

Clough chairman Keith Spence said the offer price was at a premium to the Clough's highest trading price.

“The proposal represents an opportunity for Clough shareholders to realise a premium value for their investment," Mr Spence said.

"Subject to the conditions being satisfied, the Clough independent directors intend to unanimously support the transaction.”

In June, Clough upgraded its guidance for fiscal 2013 earnings before interest and tax forecast to $90 million on revenue of $1.5 billion, on the back of a strong quarterly performance and cost-saving measures.

Fiscal 2014 revenue was tipped at $1.35 billion.

M&R first invested in Clough in 2003.

The proposal is conditional on due diligence, M&R board approval and a unanimous recommendation by Clough independent directors.

An independent expert would also have to judge the deal as being in shareholders' best interests and it was subject to no superior proposal emerging.

Clough will allow M&R access to confidential information, as part of its due diligence, until 31 August.