The Defence Secretary will urge Jeremy Hunt to boost defence spending during a crunch meeting with the Chancellor.
Speaking to Forces News, Ben Wallace says he will "make sure that, in this difficult economic time, defence gets its fair share" at their meeting on Thursday.
He added: "The priority, as I've said, is defence, these days – it's up the political agenda."
The Government committed to increasing defence spending to 3% of GDP by 2030 under former Prime Minister Liz Truss.
Mr Wallace also reiterated that all the Conservative candidates, in their leadership pitches earlier this year, made pledges about defence spending, adding "the Chancellor himself pledged 3% by 2028".
On Wednesday, Mr Wallace told the Commons Defence Committee that he will be "fighting for as much money as I can get" for defence when meeting the Chancellor ahead of the 17 November autumn statement.
He also denied that he has threatened to resign if he failed to secure a commitment from Rishi Sunak to increase defence spending as a share of national income.
Earlier this week, Mr Wallace said he would like to see defence spending go up "by significant amounts" – but acknowledged he lives "in the real world".
He said he is "confident" there is a "recognition that defence is moving up the funding priority ladder".
He said it will be revealed in the upcoming budget "how fixed" the new Prime Minister and Chancellor are on raising defence spending to 3% of GDP.