Macmahon Holdings has become the latest WA-based engineering and construction contractor to say Fortescue Metals Group's deferall of expansion plans will have little to no effect on its bottom line.

Macmahon was awarded a $340 million contract in December last year, to construct a 53 kilometre rail line from the Solomon mine in the Pilbara to Fortescue's main Pilbara network.

The engineering and contracting group today advised shareholders there would be no change or impact to the contract.

Fortescue deferred $1.6 billion of capital expenditure yesterday and cut several hundred jobs.

NRW Holdings called a trading halt after Fortescue's announcement, while Calibre Group, RCR Tomlinson and Forge Group all claimed they did not expect any material impact from the deferral.

At 12:20PM, Macmahon stocks were down 4.5 per cent, trading at 53 cents.