Takeover target Spotless Group has finally caved in and "reluctantly" recommended to its shareholders that they accept a $1.2 billion offer from Downer EDI.

In statements issued to the stock exchange on Tuesday morning, Spotless announced an overhaul of its directors that would see Downer granted four board seats in line with its 67 per cent shareholding.

That stake has been pieced together over recent months as part of an arduous takeover process that was opposed throughout by the Spotless board.

The shakeout will see two Downer directors, Philip Garling and Grant Throne, join the Spotless board as well as Downer's chief financial officer, Michael Ferguson, and a former Downer director, John Humphrey.

Garry Hounsell will stay on as Spotless chairman while director Simon McKeon and Spotless chief executive Martin Sheppard will keep their board seats.

"We continue to believe in the strong underlying fundamentals of the Spotless business, however, now that Downer owns 67.279 per cent of Spotless and will control a majority of the board from Wednesday, on balance, we reluctantly recommend that shareholders accept the Downer offer," Mr Hounsell said.

In June, Downer made its $1.15-a-share bid unconditional.

The Spotless statement also noted that American fund Coltrane Asset Management had not accepted the Downer offer and held 10.64 per cent of Spotless.

If Coltrane continued to hold out, that would mean Downer could not compulsorily acquire all of Spotless which could, the statement noted, prompt a "new offer to all shareholders at an improved price".

Downer also issued a statement in which it welcomed the move by the Spotless board.

It warned shareholders hoping to hold out for a better offer that there were "a number of significant risks in remaining a minority shareholder in Spotless".

Downer announced it would also extend the deadline on its off through to July 31.