This would allow the 32 NATO countries' armies to work better together by establishing common rules for procedures and equipment including artillery, ammunition and planes.

"Standards are critical to our ability to fight together and more robust standards will help reduce defence costs," NATO chief Mark Rutte said after two days of meetings with the alliance's defence ministers in Brussels.

The issue has been on NATO's agenda since its founding 75 years ago but took on greater urgency after Russia's war on Ukraine began in 2022.

For example, as weapons flowed from NATO member countries to Ukraine, Ukrainian soldiers soon discovered that supplied 155 mm shells could not always be used in field guns taking that sized ammunition.

A Dutch shell did not fit into a German cannon, a Ukrainian diplomat said last year, although that issue has since been resolved.

"There are actually almost 200 allied working groups on standards," a NATO official said this week.

In addition to the NATO push, nearly 10 member states including the United States, Britain and Germany signed a letter of intent to strengthen joint standards.

"It's more a commitment to work together and put some money behind working together on standardisation, particularly on land munitions," the official said.

NATO countries will also task Rutte with drafting proposals "to modernise the entire NATO standardisation process" by February, the official added.

The alliance has around 2,000 "standards", some of which are about procedures such as how to drive a tank without the risk of accidents.

The procedure-based ones are easy to implement.

But for equipment, that is "where we have the larger issue", the NATO official said.

NATO will first focus on ammunition -- which the official said is needed most to "win wars" -- meaning a challenging task of coordinating with the defence industry.

The alliance will push to get manufacturers involved right at the start of developing new equipment, which officials say is not currently happening.