Grant Shapps could not say when a Conservative pledge to raise defence spending would be reached, despite having warned of rising global threats.
The Defence Secretary said spending on defence was currently below the target of 2.5% of gross domestic product (GDP), a measure of the size of the economy.
“We’re comfortably above 2%,” he told Sky’s Sunday Morning With Trevor Phillips.
“But we are pledged to, when conditions allow, get to 2.5%.”
Challenged over when that goal would be hit, he told the BBC’s Sunday With Laura Kuenssberg: “There is a trajectory upwards.
“I can’t give you the exact date because we’ve always said it’s as the economic conditions allow.
“But the point is we’re working to a plan.”
He defended Chancellor Jeremy Hunt’s focus on tax cuts rather than upping defence spending, arguing “people do want to see more of the money that they earn kept”.
It came after Mr Shapps earlier this week made the case for increased western defence spending, saying the UK was facing a “pre-war world”.
In a major speech on Monday, he set out the risks posed by countries including China, Russia, Iran and North Korea as well as terrorist groups in an increasingly dangerous world.
Before taking on the defence brief, Mr Shapps had backed a level of spending in excess of the Government’s goal, arguing it should rise to 3%.
He said in his Lancaster House address that the UK has increased its funding, with a record £50 billion a year being spent on defence.
But the speech was seen viewed as a push for extra funding, both at home and by Nato allies, many of whom are not meeting the alliance’s 2% of GDP spending target.
Also this week, counter-terrorism police said Britain faced its most “acute threat” of hostile foreign interference and spying since the Cold War because of the “triple threat” of Russia, China and Iran.
And a former chief of the general staff of the British Army warned the UK risked a repeat of the 1930s unless more was invested in its armed forces.
General Lord Dannatt hit out at the shrinking size of the army, which he said had fallen from 102,000 in 2006 to 74,000 today “and falling fast”.
He drew parallels with the 1930s when the “woeful” state of the UK’s armed forces failed to deter Hitler, saying there was “a serious danger of history repeating itself”.
But Mr Shapps insisted the size of the army would not dip below 73,000 under the Tories.
He said: “It’s not projected to go down to 50,000.
“It’s actually, specifically, to 73,000 plus the reserves.”
The senior Tory went on to play down concerns about the capabilities of the British military.
It was put to him that Cabinet colleague Penny Mordaunt had warned that the Royal Navy and its partners must keep pace with the growing capabilities of other nations, otherwise Britain’s interests could not be secured.
Mr Shapps responded: “I’m in a post where there are a lot of people with opinions and a lot of people who’ve been in the military and armed forces will often express them.”
Meanwhile, shadow home secretary Yvette Cooper would not commit to Labour spending 3% of GDP a year on defence if elected.
On Sky News, she said: “Decisions for future spending if Labour wins the election would be for a Labour chancellor…
“But we have been clear about the importance of our national security.
“National security is the bedrock on which everything else in the country and everybody’s wellbeing is built and so of course that includes supporting our Armed Forces and making sure that they have the investment and the support that they need.”
Published: by Radio NewsHub