Companies engaged in tax avoidance may be barred from bidding to maintain the new Forth road bridge, according to Transport Scotland.
The Forth Replacement Crossing maintenance contract will also ensure trade union blacklisting does not happen on the bridge, according to Transport Minister Keith Brown.
He also dismissed Edinburgh Council's concerns that city taxpayers will have to pay compensation to property owners that have been disadvantaged by the bridge construction works, saying that the Government "will take on these obligations".
Speaking at Holyrood's Infrastructure and Capital Investment Committee, vice-convener Adam Ingram asked Mr Brown for an assurance that the maintenance contract will not be awarded to a company that has been found to engage in employee blacklisting, or which uses "aggressive tax avoidance measures".
Mr Brown said: "The Scottish Government abhors that kind of behaviour.
"The contract that we intend to go into will contain provisions for ethical sourcing practices which means that freedom of association and the right to collective bargaining, which has been the source of some of the blacklisting allegations that have been made, are respected.
"That means that the contract will guarantee that workers will have a right to join or form trade unions of their own choosing and to bargain collectively, and also that the employer will be required to adopt an open attitude to trade unions and that workers representatives are not discriminated against.
"So to the extent that those have been the source of the blacklisting, the contract will make sure that that does not happen."
When asked whether the ethical sourcing clause would also cover companies which avoid paying tax, Mr Brown said he is "not sure of the full extent of that clause".
Transport Scotland's head of special projects, Graham Porteous, told the committee: "Companies that have not fulfilled their tax obligations may be barred from competing but we will take advice at the time from the Scottish Government legal department about the policies that are in place at the time."