US lobby groups for agriculture and pharmaceutical firms want UK standards changed to be closer to those of the US in a post-Brexit trade deal.
The meat lobby wants the sale of growth hormone-fed beef, currently banned in the UK and EU, to be allowed in the UK.
The drugs company lobby wants changes to the NHS drugs approval process to allow it to buy more of US drugs.
They are also asking US officials - who will hold a hearing later - to seek lower tariffs on agricultural goods.
The farming groups say any deal should move away from EU standards, including rules governing genetically modified crops, antibiotics in meats, and pesticides and herbicides, such as glyphosate.
Technology groups are also setting out their wishlists for any pact. Companies in this sector are against the UK's proposed digital tax.
The UK government has promised to look at ways of taxing US technology giants, such as Amazon and Google, which critics say do not pay their fair share of tax in the UK and therefore operate at an unfair advantage to physical companies.
US companies - especially in the agricultural sector - said they hoped the UK would prove more flexible than the EU.
UK negotiations could represent "a once-in-a-lifetime opportunity", the National Grain and Feed Association and North American Export Grain Association wrote.
The groups said a new deal could create a trans-Atlantic market "that can act as a bastion against the EU's precautionary advances and its ongoing aggressive attempts to spread its influence around the globe".
