The France defender believes the FA Cup winners need more firepower, as well as replacements for Bacary Sagna and Lukasz Fabianski after they left the Emirates Stadium
France striker Giroud scored 22 goals in all competitions for Arsene Wenger's side in the 2013-14 season, but supporters at the Emirates Stadium have been vocal in their belief that the club need further attacking options.
And Koscielny, who signed a new long-term deal at the club in May, believes a forward who can contribute 30 goals per season is required if the north London outfit is to challenge for honors moving forward.
"We need to recruit a very, very good striker, because it's important for us, for competition for places, because Olivier needs that to become even better," he told reporters. "Having a striker who scores more than 30 goals a season can help us win the Premier League. Compared to the squads like Manchester City, even [Manchester] United or Chelsea, you can see there's a certain difference."
Chief executive Ivan Gazidis has revealed the club is already in deep conversations regarding potential targets, though it has been reported it isn't willing to match the 35 million-euro bids of Chelsea and Manchester City for Cesc Fabregas.
Koscielny, though, is hopeful a midfielder will be added to the squad, as well as replacements for the departing Bacary Sagna and Lukasz Fabianski .
"We'll need a goalkeeper, a right back, a midfielder and a striker. It's important to have a minimum of these four players so that we'll be better able to challenge over the course of a whole season against teams like Manchester City, Chelsea or United.
"Winning the FA Cup can change things and lead to other players coming."