The boss admitted the Premier League club - who haven't competed in the Champions League since the 2016/17 campaign - will struggle to compete with the riches of teams like Manchester United, Manchester City, Chelsea and Liverpool unless results improved on the pitch.
He's quoted by The Sun newspaper as saying: "The fact we've not been in the Champions League for the past three seasons has put an enormous amount of financial pressure on the club.
"We haven't achieved the goals we wanted in that time -- there is a reason for that. We're trying to put a plan together to improve what we have.
"If we stand still, the gap to the top teams will become bigger and bigger.
"I haven't come here to accept that, so now the challenge is to improve the squad in the right positions to give us the best chance to compete.
"The level of the big teams in this country is getting higher every year and if we want to compete with them we have to change straight away."
With top flight football resuming this week, Arteta is hopeful Arsenal can improve on their ninth place standing to secure Champions League qualification despite half of their remaining 10 league games coming against teams above them in the table.
He added: "We know that the way we finish the season can relax the financial position that we're in but we have to go game by game.
"We can't achieve anything in one or two matches. It's a ten-game process and we know the difficulty of achieving the target because there are a lot of other clubs in this fight.
"But we have to give it a go and believe that we can do it."