Mr Hague will address the Conservative Spring Forum
William Hague has accused Gordon Brown of "debasing the coinage of politics" by not holding a referendum on the European Union's Lisbon Treaty.
The shadow foreign secretary said Labour has squandered voters' trust by not giving them a say on EU reforms.
He used speech ahead of June's European elections to argue this is a betrayal of Labour's manifesto promise of a referendum on the failed constitution.
Ministers say the treaty does not carry the same weight as the constitution.
Britain became one of 25 EU nations to ratify the Lisbon Treaty, which aims to streamline the EU's institutions and replaces the failed EU constitution, after a Parliamentary vote in June last year.
The document has proved controversial, with unsuccessful attempts in the UK Parliament and the courts to force a referendum on the issue.
'Not too late'
Mr Hague used his speech to put the treaty at the heart of his party's campaign for the European Parliament elections on 4 June.
He told the Conservative Spring Forum in Cheltenham: "The message we will take to the doorsteps in the coming weeks is that if you vote Conservative it is not too late to have the referendum you were promised.
"It is not too late to send Gordon Brown a message on June 4 so loud he cannot ignore it, and it is not too late to elect a Conservative government that will fulfil the promise that all parties made at the last general election and to which only the Conservative Party has stayed true."
Mr Hague repeated the Tory promise to hold a referendum on the Treaty if it remains unratified by any of the EU's 27 states if the party is elected to government.
"It is a matter of trust; it is a matter of faith in politics; and our commitment rests on the truth that, in a democracy, lasting political institutions cannot be built without the people's consent," he is expected to argue.
Mr Hague went on to say the government has contributed to the public's "disillusionment" with politics and justified their "mistrust".
"They have not only devalued the currency of the nation, but their breaking of promises has been so brazen, and in the case of the referendum so inexcusable, that they have debased the coinage of politics itself.
"Their legacy will be to leave office with the word of government less believed than at any time in our lifetimes - another aspect of the scorched earth they will leave behind them, on which only a new government can plant the seeds of trust and belief afresh."
Tory MEP Daniel Hannan, whose three-minute European Parliament speech attacking Gordon Brown as the "devalued prime minister of a devalued government" became a worldwide hit on YouTube, gaining more than two million hits, is to address the party's spring conference on Sunday.
The Lisbon Treaty is awaiting approval by the Czech senate and president and Poland's president.
In Germany, despite parliamentary approval, the constitutional court is studying the treaty to judge whether it conflicts with the German constitution.
It will also face a second referendum in the Irish Republic, where it was rejected in 2008.
Under EU rules, the treaty cannot enter into force if any of the 27 member states fails to ratify it.