You can make an unsolicited proposal to an agency, but it must meet strict criteria to be considered.
If you think you have a strong, unique offering that a buyer has not advertised for, you can put in an unsolicited proposal.
Unsolicited proposals will only be considered when they:
If the buyer believes your proposal offers something that they need that no one else can offer, they'll complete a business case and potentially award you the contract. If it's something they need but you're not the only one who can do it, they might advertise it as an open contract opportunity and you'll have to compete for the contract.
Information on how buyers should deal with unsolicited proposals can be found here: