The Chelsea boss has repeatedly voiced his disappointment with the summer business and lamented a desperately thin squad.
Chelsea have struggled to compensate with injuries to big players this season and Conte urged the Blues board to sanction a January spending spree.
He said: ‘Manchester City’s path is incredible, no? I think Manchester City in this season is a strong team.
Chelsea 2017/18 Fixtures
Swansea (H) – Wed 29 Nov
Newcastle (H) – Sat 2 Dec
Atletico Madrid (H) – Tue 5 Dec (Champions League)
West Ham (A) – Sat 9 Dec
Huddersfield Town (A) – Tues Dec 12
Southampton (H) – Sat Dec 16
Bournemouth (H) – Wed Dec 20 (EFL Cup)
Everton (A) – Sat Dec 23
Brighton (H) – Tues Dec 26
Stoke City (H) – Sat Dec 30
‘Also last season, Manchester City were a fantastic team.
‘Then, after the transfer market, they bought their first targets and then they have improved a lot.
‘They can do this also in January maybe and in the future. For this reason, we must be worried because if we want to compete with Manchester City we have to work and make the best decisions in the market.
‘If you want to reach something important it’s very important to have a good balance.’
Chelsea managed to rescue a point against Liverpool on Saturday, but fell further behind City as the Sky Blues came from behind to beat Huddersfield on Sunday.
Conte believes Chelsea will fall further behind should the club fail to act in the transfer window.
More: Chelsea FC
City are almost certain to add to their squad in January with Pep Guardiola eyeing a centre-back after an injury to John Stones.
Chelsea spent a significant amount of money in the summer on Alvaro Morata, Danny Drinkwater, Antonio Rudiger and Tiemoue Bakayoko, but Conte missed out on several top targets.
They included striker Romelu Lukaku, who joined Manchester United, midfielders Antonio Candreva and Ross Barkley and centre-back Virgil van Dijk.