The Scottish Parliament should investigate the "fundamental mistakes" that have kept Scottish and UK companies at the margins of the £1.5 billion new Forth Bridge project, a Fife MSP has claimed.

Labour's John Park, a member of the Parliament's Economy, Enterprise and Tourism Committee and one of the few Scottish parliamentarians with industry experience, made the call after further details of the sourcing of the materials and labour for the project emerged from project director Transport Scotland (TS) following questions from the Sunday Herald.

The details suggest that, despite Scottish Government claims about the economic boost from the bridge, a key plank of the so-called "Plan McB" stimulus programme, the domestic benefit is unlikely to be more than 5% of the total value of material and labour contracts. The bridge is the largest ever civil engineering project undertaken in Scotland but the proportion of benefit flowing directly to domestic firms is believed to be the lowest ever for a project of this scale.

Park said: "There has to be some clarity and transparency about how all the contracts are being placed, and once we have that it would be useful for the infrastructure or the audit committee to look at why Scottish and UK companies are not benefiting as much as we were told. Industry, politicians and civil servants need to learn how to do projects better in terms of the legacy to industry and skills.

"There have been fundamental mistakes made here. We are in the worst economic conditions in living memory, we can't do things the way we've always done them. It can't just be about cost, it has to be about value. The Scottish Government has had four years to work out how they could structure this contract differently in a way that is still compliant with European regulations. It's down to political will. Can you imagine this happening in France or Germany or the Nordic countries?"

On Friday, TS confirmed what this newspaper reported last September, that the "deck" of the new Forth Bridge would be pre-fabricated at Zhenhua Heavy Industries near Shanghai in China, used for previous projects by American Bridge a member of the Forth Crossing Bridge Constructors (FCBC) consortium.

Experts in bridge construction have said that the giant components, weighing a total of 24,500 tonnes (66% of the bridge's steel), will be assembled on specially-made "jigs" or templates in China. These will leave the factory in a completed state, under the terms of standard quality control guarantees and stored in specially-built yards in Rosyth until required for assembly. Other steel components will come from Seville in Spain (8500 tonnes) and Gdansk in Poland (4200 tonnes).

"No Scottish firms bid to supply the huge amount of raw steel required by a project of this scale," TS said.

Last month, the Scottish Government announced the award of over £20 million worth of subcontracts to 118 Scottish firms, described as "a significant boost to the Scottish construction sector". However, with the contracts averaging £180,000 each, they are likely to be low-end subcontracts, including power supply, mobile office catering, and toilet hire and cleaning.

A further 134 subcontracts are still to be awarded, but TS has declined to comment on the nature, scale or timing of the awards, calling it "a commercial matter for the contractors". Awards on a similar scale to those already made would mean that less than 5% of the entire costs of the bridge will go into the pockets of companies based in Scotland.

The main consortium combines American Bridge from the US, Hochtief from Germany, Dragados from Spain and Galliford Try of London, all of whom are likely to employ globe-trotting workers with experience on previous projects. Second-tier contracts, comprising road works and the £13m "Intelligent Transport System" have been won by Irish firm John Graham (Dromore) Ltd, and the £25m contract to upgrade the M9 at Junction Ia was won by Sisk of Dublin and Roadbridge of Limerick. Construction sources say that much of the labour and plant will be imported from Ireland.

TS said: "This construction will support over 1200 new jobs. Every year until its completion in 2016, the construction will deliver 45 vocational training positions, 21 professional training places and 46 positions for the unemployed, as well as providing scope to maximise Modern Apprenticeship opportunities."

Alan Simpson, vice chairman of the Institution of Civil Engineers Scotland said there was "nothing unusual" in the lack of Scottish input in the largest civil engineering project ever undertaken in Scotland. "That is how bridges are procured these days."

However the lack of significant input from Scottish firms or workers in building the new Forth Crossing stands in marked contrast to the Hardanger Bridge in Norway, which is also built with steel assembled by Zhenhua Heavy Industries. That I.3km  suspension bridge across a steep ford, which involves hard-rock tunnels at both ends is being built by a largely Norwegian workforce for £200m, or about a fifth of the cost of the new Forth crossing.

In a statement, Transport Scotland claimed that "this construction will support over 1,200 new jobs... It will also deliver hugely valuable employment opportunities for school leavers, graduate engineers and those currently out of work.  Every year until its completion in 2016, the construction will deliver 45 vocational training positions, 21 professional body training places and 46 positions for the long term unemployed, as well as providing further scope  to maximise Modern Apprenticeship opportunities."