The five-time and reigning world champion Hamilton believes the difference between the sides could be as little as half-a-second.
However, despite the comfort the top three usually have, Hamilton believes the gap may have been cut and he also thinks Ferrari and Red Bull will give Mercedes more of a run in 2019.
"No, I think it is the three teams (in contention at the front), but also the teams at the back have closed up as far as I'm aware," Hamilton said to Crash.net. "The whole pack has closed up.
"I don't know which team is fourth currently, but they are a lot closer than they were before. There was like a second-gap before but now they are within half-a-second, or maybe less, which is awesome.
"So depending on how their development is during the year and whether they have the capacity to develop as quickly as the top three teams will be the question, but it will be exciting.
"Maybe we will see some races where Renault or the Racing Point will be a lot higher than they were in the past."